WALL STRUCTURES MADE USING COMPOSITE WALL PANELS

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 63/744,115, filed Jan. 10, 2025, U.S. Provisional Application No. 63/729,637, filed Dec. 9, 2024, and U.S. Provisional Application No. 63/720,649, filed Nov. 14, 2024, which are incorporated by reference in their entirety.

BACKGROUND

Technical Field

This disclosure relates to wall structures and wall construction components and systems that include a wall frame made of studs or other structural elements and lightweight composite panels as essentially flat wall elements on opposite sides of the wall frame.

Related Technology

Houses and other buildings are typically constructed using wood or metal studs to form a three-dimensional wall frame, which can include an interior wall on one side and an exterior wall on the other. Alternatively, both sides can be interior walls, such as interior walls separating rooms or walls dividing attached dwelling units such as apartments, town houses, and condominiums. In some cases, both sides can be exterior walls, such as fences, screen walls, sound barriers, walls that partially enclose carports, dumpster surrounds, and the like.

Interior walls of houses and other buildings are typically formed using drywall (e.g., gypsum board) to form a generally flat underlying wall surface, which can be painted, wallpapered, or treated with other desired finishes. A drywall panel typically consists of a layer of gypsum plaster sandwiched between two layers of paper. Gypsum plaster is made from calcium sulfate hemihydrate (or plaster of Paris) and water and mixed with fiber (typically paper and/or glass fiber), plasticizer, foaming agent, finely ground gypsum crystal as accelerator, EDTA, starch or other chelate as a retarder, and various additives that can increase mildew and fire resistance, lower water absorption (wax emulsion or silanes), and reduce creep (tartaric or boric acid). The board is then formed by sandwiching a core of the wet plaster mixture between two sheets of heavy paper or fiberglass mats. When the core sets, it is dried in a drying chamber, and the sandwich becomes rigid and strong enough for use as a building material.

While suitable for walls which are not exposed to water, ordinary gypsum board is not suitable for applications exposed to water and high humidity environments. Gypsum board is highly vulnerable to moisture due to the inherent properties of the materials that constitute it: gypsum, paper, and organic additives and binders. Gypsum will soften with exposure to moisture and turn into a gooey paste with prolonged immersion, such as during a flood or even in a bathroom when exposed to excessive water. Following water damage, drywall will likely need to be removed and replaced. Furthermore, the paper facings and organic additives mixed with the gypsum can be a breeding ground for mold.

For applications where walls will be exposed to moisture, such as in bathrooms, particularly showers and bathtubs, greenboard drywall and cement board are typically used. Greenboard is modified gypsum board in which the paper facing is treated with a waxy coating and chemicals that resist moisture and mildew. While water-resistant, greenboard is by no means waterproof. If water gets past the water-resistant layer, the gypsum core will absorb water and degrade similar to ordinary gypsum board. Cement board is a combination of cement and reinforcing fibers formed into sheets of varying thickness. Cement board is typically used as backer board for tile and other finishes. Cement board can be nailed or screwed to wood or steel studs to create a substrate for vertical tile and attached horizontally over plywood for tile floors, kitchen counters, and backsplashes. Cement board can also be used on the exterior of buildings as a base for exterior plaster (stucco) systems and sometimes as the finish system itself. Cement board adds impact resistance and strength to the wall surface as compared to gypsum boards. Cement board can be fabricated in thin sheets with polymer modified cements to allow bending for curved surfaces.

As tile backer board, cement board has better long-term performance than paper-faced gypsum core products because it does not physically break down in the continued presence of moisture or leaks and purportedly does not support mold or mildew growth. Cement board does provide a stronger bond and support with tiles than typical gypsum board but is typically made to breath and is not waterproof per se. It can absorb moisture but has excellent drying properties. In areas continually exposed to water (e.g., showers) a waterproofing material (e.g., plastic barrier) is usually placed behind the cement boards, or a trowel-applied waterproofing product (e.g., liquid membrane) can be applied to the face of the cement boards behind the finish system.

A major disadvantage of cement board is its relative high density (e.g., weight per square foot). Cement board weighs approximately twice as much as gypsum board, making handling by one person difficult. Cutting cement board must also be done with carbide-tipped tools and saw blades. Due to its hardness, pre-drilling of fasteners is often recommended. And because cement board contains fibers and many voids, pockets, and capillaries, it does in fact permit water penetration and can even support mold growth.

A major challenge with constructing conventional interior wall systems is the weight of conventional wall panels, including gypsum board, greenboard, and cement board. Another issue is that greenboard is moisture resistant but not waterproof, Therefore, even though it is somewhat lighter than cement board, it does not provide the same level of water protection. Another issue with traditional interior wallboards is their tendency to warp, have surface imperfections, or otherwise have defects that make them non-planar. As a result, it is often necessary to “float” tile and other surface finishes using thin set mortar to yield a planar finish. In the event that a planar wall surface (e.g., “level 5” surface) is required, such as when the surface finish includes paint, wallpaper or other pristine wall finish that may expose non-planar defects, it will typically be necessary to fill in surface defects and warping using plaster, which can be expensive and time consuming.

Exterior walls and wall finishes have their own unique challenges. In general, exterior walls are typically formed by fastening sheathing, typically wooden boards, to form exterior walls, followed by the application of a waterproof membrane, followed by the application of one or more surface finishes, most of which require several steps and layers. The wooden sheathing boards can be any kind of plywood. The currently preferred and most common wooden sheeting used to make exterior walls are oriented strand board (“OSB”) panels because of their favorable cost and combination of materials properties. OSB panels are typically used to form outer walls to which desired finishing elements can be attached, such as stucco, bricks, stone, panels, fixtures, and the like.

OSB is a type of engineered wood panel formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. OSB may have a rough and variegated surface with the individual strips of around 2.5 cm×15 cm (1.0 by 5.9 inches), lying unevenly across each other. OSB may be produced in a variety of types and thicknesses. OSB is sometimes confused with “chipboard”, a synonym for “particle board”, whose “chips” are of a size that a lay person would likely describe as “particles”. However, OSB is much stronger and durable than particle board and is frequently used in light steel frame house construction.

OSB panels are not waterproof but prone to swelling, rotting, and developing mold and mildew if exposed to water over time. They are typically wrapped with a waterproof polymer membrane to keep external water from contacting the OSB panels. The waterproof polymer membrane can also provide an air barrier that prevents unwanted air leakage. In addition, flashing, tape, and sealants can be used around joints to prevent water and air intrusion. Thereafter, one or more layers of other materials are applied over the polymer membrane to form a finished outer wall. At least one of the outer layers must be mechanically attached or connected to OSB panels to provide structure to hold the outer layers in place. Penetration of nails and screws through the waterproof polymer membrane, however, can potentially compromises its integrity and provide a pathway for moisture intrusion. Another issue is that OSB panels are flammable and emit toxic gases when ignited, such as during a house fire. Moreover, burning OSB panels emit embers that can quickly spread and ignite other fires, such as those which devastated entire neighborhoods near Los Angeles, California, in January 2025.

FIG. 1A illustrates a framed house 100 that has been framed using wooden studs 110 used to form wall and roof frames for interior walls, exterior walls, and roofs. Instead of wooden studs 110, wall frames can include metal studs. FIG. 1B illustrates a framed house 100 with OSB panels 120 attached to the studs to form exterior walls. FIG. 1C illustrates a framed house 100 with OSB panels forming an outer wall and house wrap 130 on the outer surface of the OSB panels to form a waterproof exterior wall. The house wrap 130 is typically a waterproof polymer membrane that protects the OSB panels from water damage and can also provide an air barrier that prevents air leakage. FIG. 1D illustrates a framed house 100 to which a stucco finish 160 is being applied with the aid of scaffolding.

Modified OSB panels, such as those uses in the ZIP Wall Sheathing System (“ZIP System”), include OSB panels to which an integrated water-resistive barrier has been applied. This reportedly eliminates the need to wrap the ZIP System modified OSB panels with a waterproof polymer membrane, saving time and labor costs. ZIP System panels may also include an insulating foam layer positioned between the modified OSB units and underlying structural wall elements. This is known as the ZIP System Insulated R-Sheathing (“ZIP-R System”).

FIG. 2A illustrates a modified OSB panel 200 used in the ZIP-R System, which includes a structural OSB layer 210, a water-resistant barrier layer 220 on the outer surface of the OSB layer 210, and an insulating foam layer 230 on the inner surface of the OSB layer 210. FIG. 2B illustrates a wall 240 that includes a wall frame 242 comprising studs 244 and a plurality of ZIP System modified OSB panels 200 attached to the wall frame 242. Because an exterior wall made using modified OSB panels 200 to form a Zip System wall is not typically wrapped with a polymer membrane, adjacent modified OSB panels 200 form joints or seams that must be sealed using strips of flexible waterproofing tape 246 (e.g., flexible composite acrylic tape) to provide a waterproof barrier and also prevent unwanted air leakage.

Stucco is a common finish applied to exterior walls of houses, apartments, town houses, condominiums, and other buildings. There are two main stucco systems: traditional stucco systems and exterior insulation and finish systems (EIFS). Both require the application of multiple layers of different materials that are heavy, time consuming, labor intensive, and in some cases bulky, hard to manipulate and apply, and potentially dangerous and when standing on scaffolding.

FIG. 3A illustrates a traditional stucco system 300 in which a building with exterior sheathing 302 comprising wooden boards (e.g., OSB panels) is wrapped with one or more layers (e.g., polymer membrane 130 as illustrated in FIG. 1C and/or a black paper layer 304 as illustrated in FIG. 3A) to provide protection against moisture instrusion. Next, lath, which is typically some type of wire mesh 306, is installed over the one or more outer protective layers 304, typically using staples and/or nails. A scratch coat 308 made from sand, cement, water, and optional components is applied over the lath 306 using a trowel or sprayer, followed by forming rough horizontal ridges and troughs using a scarifier tool while the scratch coat is in a plastic state. A brown coat 310 made from sand, cement, water, and optional components is applied over the scratch coat 308 to provide a smooth surface to which the stucco finish is applied. The scratch coat 308 provides both mechanical and chemical bonding of the brown coat 310. Finally, a stucco finish 312 is applied over the brown coat 310. Cement-based stucco is typically applied directly to the brown coat 310. If acrylic stucco is the final finish layer 312, a primer 314 can be applied to the brown coat 310 to improve adhesion and prevent delamination of the acrylic stucco finish 312.

FIG. 3B illustrates an EIFS stucco system 350 in which a building with exterior sheathing 352 comprising wooden boards (e.g., OSB panels) is coated with a liquid moisture barrier material, which hardens into a solid moisture barrier layer 354. A primer 356 is applied over the moisture barrier layer 354, and a rain screen, e.g., an adhesive layer 358 with spaced apart notches or ridges that act as vertical drainage channels is applied to the primer 356. An insulating foam layer 360 is placed over the adhesive layer 358, which bonds the foam layer 360 to the wall. A base coat 362 with embedded mesh 364 is applied over the foam layer 360. The base coat 362 can comprise thin set mortar, optionally with a primer (or a primer can be applied over the base coat 362). In some cases, as second base coat may be applied to fully embed and hide the mesh 364. Finally, a stucco finish 366 is applied over the base coat 362. The stucco finish is typically acrylic stucco, which is why a primer may be required on or in the base coat 362. Alternatively, the stucco finish can be cement stucco.

Accordingly, there remains a need for simplified methods and systems for constructing wall structures, including wall structures that have interior and exterior walls, two interior walls, or two exterior walls, of houses or other building structures that can reduce the number of required layers of materials, reduce time and cost, and improve safety compared to traditional wall structures and wall constructions systems.

SUMMARY

Disclosed are methods and systems for constructing wall structures that include a wall frame and lightweight composite panels on (e.g., covering) first and second sides of the wall frame. The wall frame typically includes a plurality of studs, which can be wooden studs and/or metal studs, and optionally sheathing on at least one side of the wall frame. The wall structure may include an interior side and an exterior side opposite the interior side, such as an exterior wall structure of a house or other building. Alternatively, the wall structure may include a first interior side and a second interior side opposite the first interior side, such as an interior wall structure of a house or other building (e.g., within a single house of building or a wall that separates adjacent dwelling units, such as apartments, town houses, and condominiums). The wall structure may alternatively include a first exterior side and a second exterior side opposite the first exterior side, such as an exterior wall structure (e.g., a fence, sound barrier, carport wall, or dumpster enclosure).

In some embodiments, a method of constructing a wall structure comprises: (1) forming or providing a wall frame, the wall frame comprising (a) a plurality of studs or other structural elements and (b) optionally sheathing forming at least one side of the wall frame; (2) fastening a first plurality of lightweight composite panels to a first side of the wall frame to form a first wall substructure; and (3) fastening a second plurality of lightweight composite panels to a second side of the wall frame opposite the first side to form a second wall substructure opposite the first wall substructure, (4) the lightweight composite panels each comprising: (a) a foam core (e.g., polymer- or inorganic-based) having a first surface, a second surface opposite the first surface, a first edge forming a perimeter of the first surface, a second edge forming a perimeter of the second surface, and side surfaces extending between the first and second edges; (b) a first protective layer (e.g., first fiber mesh reinforced cementitious layer, thermoset polymer, or other rigid material) formed over and covering at least a portion of the first surface of the foam core; and (c) a second protective layer (e.g., second fiber mesh reinforced cementitious layer, thermoset polymer, or other rigid material) formed over and covering at least a portion of the second surface of the foam core, (d) wherein the lightweight composite panels are positioned so that one protective layer faces toward, and the other protective layer faces away from, the wall frame.

In some embodiments, a wall structure comprises: (1) a wall frame, the wall frame comprising (a) a plurality of studs or other structural elements and (b) optionally wall sheathing; (2) a first plurality of lightweight composite panels fastened to a first side of the wall frame and forming a first wall substructure; and (3) a second plurality of lightweight composite panels fastened to a second side of the wall frame opposite the first side to form a second wall substructure opposite the first wall substructure, (4) the lightweight composite panels each comprising: (a) a foam core (e.g., polymer- or inorganic-based) having a first surface, a second surface opposite the first surface, a first edge forming a perimeter of the first surface, a second edge forming a perimeter of the second surface, and side surfaces extending between the first and second edges; (b) a first protective layer (e.g., first fiber mesh reinforced cementitious layer, thermoset polymer, or other rigid material) formed over and covering at least a portion of the first surface of the foam core; and (c) a second protective layer (e.g., second fiber mesh reinforced cementitious layer, thermoset polymer, or other rigid material) formed over and covering at least a portion of the second surface of the foam core, (d) wherein the lightweight composite panels are positioned so that one protective layer faces toward, and the other protective layer faces away from, the wall frame.

In some embodiments, the wall frame comprises at least one of wooden studs or metal studs. In some cases, the wall frame may omit wall sheathing, in which case the first and second plurality of lightweight composite panels can be directly fastened to the studs (e.g., wooden studs or metal studs) and/or other structural elements of the wall frame. In other cases, the wall frame includes sheathing (e.g., plywood or OSB panels) fastened to the studs to form at least one of the first or second sides of the wall frame. In such cases, at least some of the first or second plurality of lightweight composite panels are fastened to the sheathing.

In some embodiments, the first wall substructure comprises an interior wall of the wall structure. In such case, at least some of the first plurality of lightweight composite panels forming the first wall substructure can have a show layer selected from a plaster finish, polymer finish, or paper facer on or covering the protective layer under the show layer. An interior finish, such as paint, wallpaper, and/or molding may be applied to the show layer or other exposed surface of the lightweight composite panels. In addition, or as an alternative, to lightweight composite panels with show layer, the first wall substructure can provide a substrate for kitchen or bathroom finishes, such as finishes selected from tile, stone, artificial stone, or polymer finish (e.g., cultured marble). In such case, the first plurality of lightweight composite panels may omit the plaster finish, polymer finish, or paper facer in order for the fiber mesh reinforced cementitious (or other protective) layer to provide a bonding surface to which kitchen or bathroom finishes can be attached (e.g., using thin set mortar, mastic, and/or adhesive).

In some embodiments, the second wall substructure may comprise a second interior wall of the wall structure, such as where the wall structure is an interior wall of a single building or dwelling unit or is a dividing wall between adjacent, connected dwelling units, such as apartments, town houses, and condominiums. In such cases, the second plurality of lightweight composite panels forming the second wall substructure may comprise lightweight composite panels having a show layer (e.g., plaster finish, polymer finish, or paper facer) on or covering the protective layer and/or may have an exposed protective layer that provides a substrate for kitchen or bathroom finishes, such as tile, stone, artificial stone, or polymer finish (e.g., cultured marble).

Alternatively, the second wall substructure may comprise an exterior wall of the wall structure, such as where the wall structure is or forms an exterior wall of a house or building. In such case, the wall frame may or may not include sheathing other than the second plurality of lightweight composite panels. In some cases, the wall frame may require conventional sheathing. For example, the wall frame may include plywood or OSB panels fastened to studs or other structure elements to form the second side of the wall frame to which lightweight composite panels are attached. In such case, the second plurality of lightweight composite panels can be fastened to the sheathing. The second plurality of lightweight composite panels may include an exterior finish applied thereto, such as stucco, brick veneers, stone, masonry, tiles, or other exterior finishes. The exterior finish can be factory applied before constructing the exterior wall and/or applied to an exterior surface of the lightweight composite panels after forming the exterior wall substructure.

In yet other embodiments, the first and second wall substructure may comprise first and second exterior walls of the wall structure, such as where the wall structure is an exterior wall structure, such as a fence, sound barrier, carport wall, or dumpster enclosure. In such cases, the first and second plurality of lightweight composite panels may include a finish applied, such as stucco, brick veneers, stone, masonry, tiles, or other exterior finishes.

In the case where the wall structure includes an exterior wall, the exterior-facing fiber mesh reinforced cementitious (or other protective) layer of the lightweight composite panels can provide a bonding substrate to which an exterior stucco finish can be directly applied and adhere without the need for lath and other underlying layers. Other surface finishes, such as brick veneers, stone, masonry, and tiles, can be applied and adhered directly to the exterior-facing fiber mesh reinforced cementitious (or other protective) layer, such as using thin set mortar or adhesives. Because the lightweight composite panels are strong, they can support relatively heavy loads, such as multiple layers of stucco finish, brick veneers, stone, masonry, tiles, light fixtures, and other fixtures using nails, other hangers, construction adhesive, or other wall attachment systems. The composite panels are lightweight yet waterproof and have high structural strength (i.e., high tensile and flexural strength and high toughness).

The first and second lightweight composite panels can be fastened to the wall frame using mechanical fasteners and adhesives known in the art, such as wood screws, self-drilling/tapping metal screws, nails, rivets, and construction adhesive. Mechanical fasteners, particularly in the case of an exterior wall or interior wall exposed to moisture, are advantageously corrosion resistant. Strips of tape can be used as a template to ensure proper placement of screws or other mechanical fasteners when fastening lightweight composite panels to studs or other structural elements of the wall frame. To prevent screws from tearing through the exterior fiber mesh reinforced cementitious (or other protective) layer, screws can be used with enlarged washers or pan head screws or screws with integrated washers having high surface area to distribute the pressure or load over a high surface area of the lightweight composite panel. Specialized washers with penetrating prongs can be used to limit rotation and penetration, preventing damage to the lightweight composite panels. Rectangular washers with multiple prongs on either side of the screw can be used to tie adjacent lightweight composite panels together.

In some embodiments, the fiber mesh reinforced cementitious (or other protective) layers of the lightweight composite panels can have a grid pattern or other discontinuity that provide a bonding substrate that facilitates adhesion of cementitious materials, thin set mortar, seam coats, stuccos (cement- and/or acrylic-based), adhesives, paint, or other coatings to surfaces of lightweight composite panels. For example, one or more stucco layers can directly adhere to the exterior-facing fiber mesh reinforced cementitious (or other protective) layer without the need for wire mesh, scratch coat, and brown coat used in conventional stucco systems. Nevertheless, it may be desirable to apply a layer of an appropriate seam coat (e.g., thin set mortar or fine-sanded stucco) to cover screws, sealants, holes, or other discontinuities prior to applying a finished stucco layer (which can be cement-based or acrylic-based stucco). Both cement-based stucco and acrylic-based stucco can adhere directly to the fiber mesh reinforced cementitious (or other protective) layer of the lightweight composite panels. Thus, a primer coat (e.g., primer paint or other polymer-based primer) is typically not required when using acrylic-based stucco (although this disclosure permits the use of a primer if desired).

The textured surface provided by the interior-facing fiber mesh reinforced cementitious (or other protective) layer provides a bonding substrate that facilitates adhesion of lightweight composite panels to the wall frame. In such cases, an appropriate adhesive, such as construction adhesive, can be used to adhere the lightweight composite panels to the wall frame, either in addition to or instead of screws or other mechanical fasteners. The use of an adhesive provides a much more continuous bond interface between lightweight composite panels and studs or exterior sheathing, thereby distributing the load more evenly and improving shear strength. Screws used by themselves may create discrete attachment points that theoretically may become potential weak points under high shear stresses. The use of adhesive attachment in addition to or instead of screws eliminates these discrete attachment points, creating a more solid and continuous bond that can better resist lateral forces. Screws, nails, rivets, mechanical fasteners, and adhesives are examples of means for fastening lightweight composite panels to studs or sheathing of a wall structure.

Additional features and advantages will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the embodiments disclosed herein. It is to be understood that both the foregoing brief summary and the following detailed description are exemplary and not restrictive of the embodiments disclosed herein or as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, characteristics, and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings and the appended claims, all of which form a part of this specification. In the Drawings, like reference numerals may be utilized to designate corresponding or similar parts in the various Figures, and the various elements depicted are not necessarily drawn to scale, wherein:

FIG. 1A illustrates a framed house with exposed studs forming exterior wall and roof frames prior to attachment of OSB panels;

FIG. 1B illustrates a framed house with OSB panels attached to the exterior wall and roof frames of the framed house;

FIG. 1C illustrates a framed house to which a waterproof polymer membrane has been applied over the OSB panels of the exterior wall;

FIG. 1D illustrates a building to which a stucco finish is being applied to the exterior wall with the assistance of scaffolding;

FIG. 2A illustrates a modified OSB panel that includes an OSB structural core, a waterproof layer on an outer surface, and optionally an insulating layer on an inner surface;

FIG. 2B illustrates a wall frame to which modified OSB panels have been attached, with joints or seams between adjacent modified OSB panels sealed using tape;

FIG. 3A illustrates a traditional stucco system, including the various layers applied over exterior sheathing comprising OSB panels;

FIG. 3B illustrates an exterior insulation and finish system (EIFS), including the various layers applied over exterior wall sheathing;

FIG. 4A is a cross-section view of a wall structure that includes a wall frame made of studs or other structural elements and lightweight composite panels on opposite sides of the wall frame;

FIG. 4B is an exploded view of the wall structure of FIG. 4A;

FIG. 5A is a side elevation view of a lightweight composite panel for use in making wall structures of the disclosure;

FIG. 5B is a side elevation view of a building panel with show layer made from a lightweight composite panel for use in making wall structures of the disclosure;

FIG. 6A is a cross-section view of a wall structure that includes a wall frame made of studs or other structural elements, wall sheathing on one side, and lightweight composite panels on opposite sides of the wall frame;

FIG. 6B is an exploded view of the wall structure of FIG. 6A;

FIG. 7A is a side perspective view that illustrates examples of differently sized lightweight composite panels that can be used to make wall structures of the disclosure;

FIG. 7B is a top perspective view that illustrates the differently sized lightweight composite panels of FIG. 7A;

FIG. 7C is an exploded view diagram that schematically illustrates the layered structure of the lightweight composite panels of FIGS. 7A and 7B;

FIG. 8A is a perspective view that illustrates an example composite wall panel, with the different layers being visible, including a textured finish layer;

FIGS. 8B-8D illustrate an example composite wall panel, with the different layers being visible, including a smooth finish layer;

FIG. 9 is a perspective view that schematically illustrates an embodiment of a composite wall panel with bevels extending to each of the four edges;

FIG. 10A is a cross-sectional view that schematically illustrates the layered structure of an embodiment of a composite wall panel with beveled edges;

FIG. 10B is an exploded diagram that schematically illustrates the layered structure of the composite wall panel of FIG. 10A;

FIG. 11A is a cross-sectional view that schematically illustrates the layered structure of another embodiment of a composite wall panel with beveled edges;

FIG. 11B is an exploded diagram that schematically illustrates the layered structure of the composite wall panel of FIG. 11A;

FIG. 12A illustrates a pair of composite wall panels abutting each other, with beveled edges forming a channel or depression that can be filled with tape and drywall patch during installation;

FIG. 12B illustrates a pair of composite wall panels abutting each other, with the beveled edges covered by drywall patch or plaster;

FIG. 13A is a cross-sectional view that schematically illustrates the layered structure of an embodiment of a laminated composite wall panel with beveled edges;

FIG. 13B is an exploded diagram that schematically illustrates the layered structure of the laminated composite wall panel of FIG. 13A;

FIG. 13C illustrates an embodiment of a laminated composite wall panel with beveled edges;

FIG. 13D illustrates another embodiment of a laminated composite wall panel with a planar surface;

FIGS. 14A and 14B illustrate examples of lightweight composite panels for exterior use with an attached drainage layer with gaps or channels that facilitate removal of moisture from between the lightweight composite building panel and an exterior wall or roof structure to which it is attached;

FIGS. 14C-14E illustrate outdoor systems for applying a desired cladding or exterior finish to an exterior wall of a building and means (e.g., an air gap and metal flashing) for permitting air flow and removal of moisture from spaces between the cladding or exterior finish and the exterior wall;

FIGS. 15A and 15B illustrate a wall structure that includes a wall frame made of studs and OSB sheathing on an exterior side of the wall frame, a lightweight composite panel on the interior side, and a lightweight composite panel fastened to the OSB sheathing and having a stucco finish on the exterior side;

FIG. 16A is perspective view of a model that illustrates an example wall structure that includes a wall frame made of wooden studs and OSB sheathing on an exterior side of the wall frame, lightweight composite panels on an interior side, lightweight composite panels fastened to the OSB sheathing in various stages of being joined and finished on the exterior side, and lightweight composite panels covering the ends of the wall frame;

FIG. 16B is a perspective view of another model that illustrates an example wall structure that includes a wall frame made of wooden studs, sheathing on one side of the wall frame, a lightweight composite panel on the opposite side of the wall frame, and lightweight composite panels covering the ends of the wall frame;

FIG. 16C is a perspective view of another model that illustrates an example wall structure that includes a wall frame made of wooden studs, sheathing on one side of the wall frame, and a lightweight composite panel on the opposite side of the wall frame;

FIG. 16D is a perspective view of another model that illustrates an example wall structure that includes a wall frame made of wooden studs, sheathing on one side of the wall frame, and lightweight composite panels with show layer on an opposite side of the wall frame in various stages of being joined and finished;

FIG. 17 is a side view of a model of a side-by-side comparison of a simplified stucco finish applied to a lightweight composite panel and a traditional stucco system;

FIG. 18A is an exploded view of an example embodiment of a stucco system that incorporates a lightweight composite panel substrate, drainage layer, and OSB panel as sheathing;

FIG. 18B schematically illustrates an assembled view of the stucco system of FIG. 18A;

FIG. 19A is a perspective view of a model that illustrates an example wall structure that includes a wall frame made of wooden studs and OSB sheathing, an uncovered interior side, and lightweight composite panels on the exterior side and ends of the wall frame in various stages of being joined and finished;

FIG. 19B is a perspective view of another model that illustrates an example wall structure that includes a wall frame made of wooden studs and OSB sheathing, an uncovered interior side, and lightweight composite panels on the exterior side and ends of the wall frame in various stages of being joined and finished;

FIG. 19C is a perspective view of another model that illustrates an example wall structure that includes a wall frame made of wooden studs and OSB sheathing, an uncovered interior side, and lightweight composite panels on the exterior side and ends of the wall frame in various stages of being joined and finished;

FIG. 19D is a perspective view of another model that illustrates an example wall structure that includes a wall frame made of wooden studs and OSB sheathing, an uncovered interior side, and lightweight composite panels on the exterior side and ends of the wall frame in various stages of being joined and finished;

FIG. 20A is a schematic diagram that illustrates a complete wall structure that includes interior and exterior lightweight composite panels fastened to an underlying wall frame;

FIG. 20B is a schematic diagram that illustrates another complete wall structure that includes interior and exterior lightweight composite panels fastened to an underlying wall frame;

FIG. 20C illustrates an exterior side of a wall structure that includes lightweight composite panels fastened to an underlying wall frame;

FIG. 21A illustrates exterior surfaces of a wall structure that includes lightweight composite panels fastened to exterior wall sheathing of a wall frame and a stucco finish applied over a portion of the composite panels;

FIG. 21B illustrates an exterior side of a wall structure that includes lightweight composite panels fastened to exterior wall sheathing of a wall frame and examples of various exterior finishes on the lightweight composite panels, including stucco, brick veneers, stone, masonry, and tiles;

FIG. 22 illustrates mesh tape used as a template for proper placement of screws or other mechanical fasteners when fastening lightweight composite panels to studs or other structural elements of a wall frame;

FIG. 23 illustrates a composite panels with plaster layer with holes caused by screws with heads that penetrate through the plaster layer and underlying fiber mesh reinforced cementitious layer and a screw with a washer that did not penetrate through the cementitious layer; and

FIGS. 24A-24D illustrate embodiments of specialized washers with multiple prongs designed to penetrate at least partially through and become embedded within lightweight composite panels used to make wall structures of the disclosure.

DETAILED DESCRIPTION

I. Introduction

Disclosed are methods and systems for constructing interior and/or exterior wall structures that include a wall frame and lightweight composite panels on and/or fastened to first and second sides of the wall frame. The wall frame includes studs (e.g., wooden and/or metal studs), and may optionally including sheathing (e.g., OSB panels) on at least one side of the wall frame.

The wall structure may include or provide an interior side and an exterior side opposite the interior side, such as where the wall structure is or forms an exterior wall of a house or other building. Alternatively, the wall structure may include or provide a first interior side and a second interior side opposite the first interior side, such as wherein the wall structure is or forms an interior wall of a house or other building (e.g., within a single house of building or that separates adjacent dwelling units, such as apartments, town houses, and condominiums). The wall structure may alternatively include first and second exterior sides, such as where the wall structure is or forms an exterior wall that is not part of a house or building (e.g., a fence, sound barrier, carport wall, or dumpster enclosure).

Additional information relating to lightweight composite panels generally, modifications thereof, and various uses in making interior walls and exterior walls is disclosed in U.S. Application No. 63/686,489, filed Aug. 21, 2025. Additional information relating to lightweight composite panels that include a plaster show layer (e.g., for interior walls) is disclosed in U.S. application Ser. No. 19/306,817, filed Aug. 21, 2025. Additional information relating to lightweight composite panels that include a paper facer (e.g., for interior walls) is disclosed in U.S. application Ser. No. 19/343,312, filed Sep. 29, 2025. Additional information relating to lightweight composite panels that include a cured polymer show layer (e.g., for interior walls) is disclosed in U.S. application Ser. No. 19/343,601, filed Sep. 29, 2025. Additional information relating to lightweight composite panels and their use as substrates in making exterior walls with various applied finishes is disclosed in U.S. application Ser. No. 19/307,007, filed Aug. 21, 2025. Additional information relating to lightweight composite panels and their use as structural sheathing (e.g., for exterior walls and roofing decks) is disclosed in U.S. application Ser. No. 19/306,800, filed Aug. 21, 2025. Additional information relating to lightweight composite panels with a pre-applied drainage layer and their use in making exterior walls is disclosed in U.S. application Ser. No. 19/306,608, filed Aug. 21, 2025. Additional information relating to lightweight composite panels and their use in making subfloors and ceiling systems is disclosed in U.S. application Ser. No. 19/307,024, filed Aug. 21, 2025. Additional information relating to lightweight composite panels and their use in making vertical shaft liners is disclosed in U.S. Provisional Application No. 63/747,543, filed Jan. 21, 2025. The foregoing applications are incorporated by reference in their entirety.

In general, lightweight composite panels, whether used to make interior walls or exterior walls, are waterproof, can be made airtight so that little or no air flows through the walls, and can provide a surface to which a variety of different finishes can be directly applied. For example, in the case of interior walls, paint, wallpaper, and/or molding (e.g., wainscot, wood paneling, or crown molding) can be applied or adhered directly to the exposed surfaces of lightweight composite panels (e.g., that include a plaster, paper, or polymer show layer for smoothness). In the case of exterior walls, various exterior finishes can be applied or adhered directly to the exposed surfaces of lightweight composite panels without the need for lath or other underlying layers. Lightweight composite panels can function as structural sheathing in place of OSB panels.

Lightweight composite panels include a strong, yet lightweight, foam core sandwiched between relatively thin fiber mesh reinforced cementitious (or other protective) layers. As a result, the lightweight composite panels are strong and can support relatively heavy loads, such as multiple layers of stucco finish, brick veneers, stone, masonry, interior or exterior molding, tiles, light fixtures, and other fixtures using nails, other hangers, construction adhesive, or other wall attachment systems. The lightweight composite panels are lightweight yet waterproof and have high structural strength (i.e., high tensile and flexural strength and high toughness). In some embodiments lightweight composite panels can function as a shear wall but are much lighter than OSB and plywood panels. The exterior-facing fiber mesh reinforced cementitious (or other protective) layer can have a textured surface or grid pattern, which provides a bonding surface that facilitates application of adhesives, thin sent mortar, stucco, or other materials thereto. The lightweight composite panels can be cut, drilled, and screwed, fastened and/or glued onto structural elements of wall frames of buildings, such as studs and sheathing. The interior-facing fiber mesh reinforced cementitious (or other protective) layer can provide a bonding surface that facilitates adhesion of lightweight composite panels to an exterior wall structure.

By way of example, FIG. 1A illustrates a framed house 100 with studs 110 that form interior and exterior wall frames to which lightweight composite panels and optional sheathing can be attached on both sides to form complete wall structures according to the disclosure. FIG. 1B illustrates a framed house 100 that includes exterior shear walls formed using OSB panels 120 to which lightweight composite panels (not shown) can be fastened for form exterior walls to which one or more exterior finishes can be directly applied. In some embodiments, the framed house 100 can be modified by replacing the OSB panels 120 with lightweight composite panels to form an exterior wall to which one or more exterior finishes can be directly applied. FIG. 1C illustrates a framed house 100 with OSB panels forming an exterior wall and house wrap 130 on the outer surface of the OSB panels to form a waterproof exterior wall. The house wrap 130 is typically a waterproof polymer membrane that protects the OSB panels from water damage and can also provide an air barrier that prevents unwanted air leakage. FIG. 1D illustrates a framed house 100 to which a stucco finish 160 is being applied with the aid of scaffolding.

FIG. 2A illustrates a modified OSB panels 200 that includes an OSB core 210, a water-resistant barrier layer 220 on an exterior surface of the OSB core 210, and an insulating foam layer 230 on the interior surface of the OSB core 210. FIG. 2B illustrates a wall 240 that includes a wall frame 242 comprising studs 244 and a plurality of modified OSB panels 200 attached to the wall frame 242. Joints or seams between adjacent OSB panels 200 are sealed from moisture and air using flexible tape 246. First lightweight composite panels (not shown) can be fastened to an interior side of the wall frame 242 to form an interior wall of a complete wall as disclosed, and second lightweight composite panels (not shown) can be fastened to the modified OSB panels 200 to form an exterior wall of a complete wall as disclosed. Alternatively, some or all of the modified OSB panels 200 can be replaced with lightweight composite panels to form an exterior wall to which one or more exterior finishes can be directly applied.

FIGS. 4A and 4B schematically illustrate an example wall structure 400 in cross-sectional and exploded views, respectively. The wall structure 400 includes a wall frame 402 made using standard 2×4 studs, a first lightweight composite panel 404 forming a first wall substructure on a first side of the wall frame 402, and a second lightweight composite panel 406 forming a second wall substructure on a second side of the wall frame 402. The first and second lightweight composite panels 404, 406 can be fastened to the wall frame 402, such as to the studs, using any fastening means known in the art, such as wood screws, self-drilling/tapping metal screws, rivets, nails, construction adhesive, and combinations thereof.

As illustrated in FIG. 4B, the first and second lightweight composite panels 404, 406 can be fastened to the wall frame 402 using screws. The first lightweight composite panel 404 is illustrated as being a drywall substitute used to make an interior wall. In such case, the first lightweight composite panel 404 can be fastened to the wall frame 402 using standard drywall screws 410. The second lightweight composite panel 406 is illustrated as being used to make an exterior wall. In such case, the second lightweight composite panel 406 can be fastened to the wall frame 402 using non-corrosive exterior screws 412 (e.g., made from stainless steel, galvanized steel, high strength polymers, and the like). To provide insulation, FIG. 4B illustrates the placement of an insulation layer 408 (e.g., mineral wool) within the space between the first and second lightweight composite panels 404, 406.

FIGS. 5A and 5B illustrate exterior surface views of first and second lightweight composite panels 504, 506, which are similar to first and second lightweight composite panels 404, 406 in FIGS. 4A and 4B. The first lightweight composite panel 504 is illustrated in FIG. 5B as having a smooth surface (e.g., formed from a plaster, polymer, or paper layer as show surface) and being attached to studs of a wall frame (not shown) using drywall screws 510 of ordinary spacing (e.g., 16 inches apart in the horizontal and vertical directions), similar to drywall screws 410 used in FIGS. 4A and 4B. The second lightweight composite panel 506 is illustrated in FIG. 5A as having a grid patten on the surface (e.g., an exterior fiber mesh reinforced cementitious layer) and being attached to studs of a wall frame (not shown) using non-corrosive exterior screws 512 of ordinary spacing (e.g., 16 inches apart in the horizontal and vertical directions), similar to the non-corrosive screws 412 used in FIGS. 4A and 4B.

It will be appreciated that the wall structure 400 illustrated in FIGS. 4A and 4B can have interior and exterior sides 404, 406 as shown or, alternatively, can have two interior sides, such as when used as an interior wall within a house or building or when used to separate two dwelling units (e.g., apartments, town houses, or condominiums). In such case, the insulation layer 408 can be omitted or it may be included to provide soundproofing. Alternatively, the wall structure 400 illustrated in FIGS. 4A and 4B can have two exterior sides, such as when used for a different purpose than as part of a house or other building (e.g., as a fence, sound barrier, carport wall, or dumpster enclosure). In such case, the first and second lightweight composite panels can be attached to the wall frame using non-corrosive exterior screws or other weatherproof fastening means.

FIGS. 6A and 6B schematically illustrate another example wall structure 600 in cross-sectional and exploded views, respectively. The wall structure 600 includes a wall frame 602 made using standard 2×4 studs, a first lightweight composite panel 604 forming a first wall substructure on a first side of the wall frame 602, and a second lightweight composite panel 606 forming a second wall substructure on a second side of the wall frame 602. This embodiment differs from the embodiment of FIGS. 4A and 4B in that it includes wall sheathing 608 and a drainage layer 610 interposed between the second lightweight composite panel 606 and the wall frame 602. The wall sheathing 608 may comprise conventional wooden sheathing, such as plywood or oriented strand board (OSB), or it may comprise an underlying layer of lightweight composite panels. In the case of wooden wall sheathing 608, the wall structure 600 may include polymer wrap (not shown) to provide waterproofing and an air barrier. Alternatively, the wall sheathing 608 may comprise modified OSB panels (e.g., Zip system OSB panels) that have a waterproof coating. In such case, polymer tape (not shown) may be used to seal joints or seams between adjacent modified OSB panels and other structural elements (see FIGS. 2A and 2B). The drainage layer 610 provides additional moisture protection to the wall sheathing 608 by providing a pathway for the removal of water vapor and condensed water.

The first and second lightweight composite panels 604, 606 can be fastened to the wall frame 602, such as to the studs, using any fastening means known in the art, such as wood screws, self-drilling/tapping metal screws, rivets, nails, construction adhesive, and combinations thereof. As illustrated in FIG. 6B, the first and second lightweight composite panels 604, 606 can be fastened to the wall frame 602 using screws. The first lightweight composite panel 604 is illustrated as being a drywall substitute used to make an interior wall. In such case, the first lightweight composite panel 604 can be fastened to the wall frame 602 using standard drywall screws 614. The second lightweight composite panel 606 is illustrated as being used to make an exterior wall. In such case, the second lightweight composite panel 606 can be fastened to the wall frame 602 using non-corrosive (e.g., stainless steel) exterior screws 616. To provide insulation, FIG. 6B illustrates the placement of an insulation layer 608 (e.g., mineral wool) within the space between the first and second lightweight composite panels 604, 606.

In some embodiments, specialized washers with penetrating prongs can be used to fasten lightweight composite panels to wall frames (see discussion of FIGS. 24A-24D below). When screws with specialized washers are driven through the lightweight composite panels and into an underlying wooden or metal stud, sheathing, or other structural element of a wall structure, the penetrating prongs of the washers will penetrate into and become embedded within the lightweight composite panels, including at least the exterior-facing fiber mesh reinforced cementitious (or other protective) layer and at least partially through the foam core. The interaction between washer prongs and lightweight composite panels prevents the washers from rotating out of place during placement and provides additional lateral strength to hold the lightweight composite panels in place relative to the wall frame. In addition, rectangular or other appropriately shaped washers with multiple prongs on either side of the screw can be used to tie adjacent lightweight composite panels together, which can improve the structural integrity and shear strength of a wall structure, such as an exterior wall structure carrying an exterior wall finish.

In some embodiments, the length of penetrating prongs of the washers can be made to correspond to the cross-sectional thickness of the lightweight composite panels used to make a wall structure. Advantageously, the length of the penetrating prongs can be slightly less than, equal, or slightly exceed the cross-sectional thickness of the lightweight composite panels. This allows the penetrating prongs to penetrate all the way through the foam core and the interior fiber mesh reinforced cementitious (or other protective) layer and make abutment with studs, sheathing, or other structural element of the wall frame. This provides a stop that limits further movement of the enlarged washer toward the lightweight composite panel, preventing unwanted crushing of the lightweight composite panel and ensuring that the screw and washer ensemble does not break through and damage the exterior fiber mesh reinforced cementitious (or other protective) layer. However, it may be desirable for the length of the prongs to permit slight compression of the exterior fiber mesh reinforced cementitious (or other protective) layer without damaging it. This ensures that appropriately strong pressure is applied by the washer to the exterior fiber mesh reinforced cementitious (or other protective) layer to securely fasten the lightweight composite panels to a wall frame. Where the underlying studs or other structural element are metal, the length of the penetrating prongs can be approximately equal to or slightly less than the cross-sectional thickness of the lightweight composite (or other protective). Alternatively, where the underlying studs, sheathing, or other structural elements are made of wood, the length of the penetrating prongs can be the same as or slightly greater than the cross-sectional thickness of the lightweight composite (or other protective) in order to for the prongs to partially penetrate into the wood, thereby potentially further increasing the lateral and shear strength provided by the lightweight composite (or other protective) of a wall structure, such as an exterior wall structure to which an exterior finish is applied.

In some embodiments, the fiber mesh reinforced cementitious (or other protective) layers of the lightweight composite panels can have a grid pattern or other discontinuity that facilitates adhesion of cementitious materials, thin set mortar, stucco (cement- and acrylic-based), adhesives, paint, or other coatings to exposed surfaces of the lightweight composite panels. For example, one or more stucco layers can directly adhere to the exterior-facing fiber mesh reinforced cementitious (or other protective) layer without the need for wire mesh, scratch coat, and brown coat used in conventional stucco systems. Nevertheless, it may be desirable to apply patches of an appropriate seam coat (e.g., thin set mortar or fine-sanded stucco) to cover screws, washers, sealants, holes, fiber mesh tape, or other discontinuities prior to applying a finished stucco layer (which can be cementitious or acrylic based).

In some embodiments, where lightweight composite panels form an exterior wall of a wall structure, a drainage layer can be optionally positioned between wall sheathing (e.g., OSB or other wooden sheathing) and lightweight composite panels to which an exterior finish is applied to facilitate removal of water and prevent damage beneath the exterior finish.

II. Lightweight Composite Panels

The wall structures disclosed herein include lightweight composite panels on or fastened to both sides of the wall frame. Lightweight composite panels can be used to make both interior and exterior wall structures to which one or more interior and/or exterior finishes can be applied. Lightweight composite panels comprise a strong, yet lightweight, foam core and a layer of fiber mesh reinforced cementitious composition (or other protective layer) on opposing sides of the foam core. As a result, the lightweight composite panels are strong and can support relatively heavy loads, such as decorative or structural features attached to wall structure. Examples include, but are not limited to, paint, wallpaper, molding, stucco (underlying and finish layers), brick veneers, stone, masonry, shingles, clay tiles, light fixtures, sheet metal, and fixtures.

A. Core Structure and Manufacture of Lightweight Composite Panels

FIGS. 7A and 7B illustrate examples of lightweight composite panels 700a, 700b, 700c of varying cross-sectional thickness that can be used as is or modified with other features for a specific purpose. FIGS. 7A and 7B show the layered structure of the lightweight composite panels 700a, 700b, 700c, including strong, lightweight, and moisture-resistant extruded polystyrene (XPS) foam cores 710a, 710b, 710c sandwiched between first fiber mesh reinforced cementitious layers 720a, 720b, 720c and second fiber mesh reinforced cementitious layers 730a, 730b, 730c. As discussed below, in other embodiments the foam core may comprise other polymer or inorganic foam materials, and one or both protective layers may comprise a thermoset polymer or other rigid protective material.

The cross-sectional thickness of lightweight composite panels 700a, 700b, 700c can be selected based on a combination of desired properties for their intended use, such as strength, insulation, spacing between wall elements, and the like. As illustrated in FIGS. 7A and 7B, the cross-sectional thicknesses of the lightweight composite panels 700a, 700b, 700c varies mostly or entirely depending on the cross-sectional thickness of the foam cores 710a, 710b, 710c. Although not shown, when lightweight composite panels 700 of greater cross-sectional thickness are desired, it may be desirable to increase the thickness of the fiber mesh reinforced cementitious layers 720, 730 (e.g., to account for possible strength reduction caused by including a foam core 710 of greater cross sectional thickness).

FIG. 7C is in an exploded view that schematically illustrates the layered structure of a core composite panel structure 700, which is similar or identical to the lightweight composite panels 700a, 700b, 700c of FIGS. 7A and 7B. The foam core 710 can be a lightweight polymer foam made from closed cell extruded polystyrene (XPS), is lightweight, rigid, waterproof, thermally insulating, and includes two outer surfaces or faces. In some embodiments, the foam core 710 may have a density of about 30-45 kg/m³ and a compressive strength of about 250-400 kPa.

Alternatively, the foam cores 710, 710a, 710b, 710c discussed above can be made from a different polymer foam material, such as, but not limited to, expanded polystyrene foam (EPS), polyisocyanurate foam, polyurethane (PUR) foam, phenolic polymer (e.g., phenol-formaldehyde) foam, melamine polymer (e.g., melamine-formaldehyde) foam, and/or other thermoplastic or thermoset polymer known in the art that can be formed into rigid or semi-rigid foam layers. An advantage of thermoset polymer foam materials is they are generally more fire- and heat-resistant than thermoplastic polymers, with thermoset phenolic polymers in particular providing a high level of fire and heat resistance.

The properties of various polymers that can be used to make foam core layers 110, 210 are set forth in Tables 1-3.

TABLE 1
Property	XPS/EPS	Phenolic
Material Type	Thermoplastic	Thermoset (phenol-
	polystyrene	formaldehyde)
Thermal Conductivity	0.028-0.033	0.018-0.022

(W/m · K)

R-Value per inch	~5.0	6.5-7.2
Fire Resistance	Poor - melts,	Excellent - chars,
	drips	low smoke
Flame Spread (ASTM E84)	75-200	<25 (Class A)

(W/O Facer

Smoke Development (W/O

>450 (often)

<50

Facer)
Thermal Stability	~93° C. (melts)	150-175°	C.

Water Resistance

Excellent

Good (closed-cell)

Compressive Strength

200-300 kPa

100-150

kPa

Flexural Strength	Flexible, good	Brittle
Recyclability	Yes (thermoplastic)	No
Weight (kg/m3)	25-35	35-50
Cost	Low-Moderate	High

TABLE 2
Property	Melamine	PUR
Material Type	Thermoset	Thermoset
	(melamine-	(polyol +
	formaldehyde)	isocyanate)
Thermal Conductivity	0.032-0.036	0.020-0.025

(W/m · K)

R-Value per inch	~4.1-4.5	~6.0-6.5
Fire Resistance	Excellent - non-	Poor - needs FR
	melting, self-	additives

extinguishing

Flame Spread (ASTM E84)

<25 (Class A)

Varies (often >25)

(W/O Facer

Smoke Development (W/O

Very low

High

Facer)
Thermal Stability	~240° C.	~100-120°	C.

Water Resistance

Poor unless sealed

Good

Compressive Strength

Low

150-300

kPa

Flexural Strength	Very brittle	Strong
Recyclability	Limited	No
Weight (kg/m3)	7-12	30-45
Cost	High	Moderate

TABLE 3
Property	Polyiso
Material Type	Thermoset (polyisocyanurate)
Thermal Conductivity (W/m · K)	0.020-0.023
R-Value per inch	~6.0-6.5
Fire Resistance	Good - chars, often Class A
	with facer
Flame Spread (ASTM E84) (W/O Facer	<25 (Class A with facer)
Smoke Development (W/O Facer)	<150

Thermal Stability

~150°

C.

Water Resistance	Fair (can degrade if
	unprotected)

Compressive Strength

140-200

kPa

Flexural Strength	Moderate
Recyclability	Rarely recycled
Weight (kg/m3)	30-42
Cost	Moderate-High

With reference to FIG. 7C, formed over first and second outer surfaces of the foam core 710 are first and second layers of fiber (e.g., fiberglass) mesh 720b, 730b, respectively, which become embedded within respective first and second layers of fresh cementitious composition applied over the fiber mesh layers 720b, 730b, which harden or cure to form first and second cementitious layers 720a, 730a. Together, the hardened cementitious layers 720a, 730a and embedded fiberglass mesh layers 720b, 730b form first and second fiber mesh reinforced cementitious layers 720, 730, which adhere to the foam core 710 to form a strong but lightweight composite panel structure. The fiber mesh layers 720b, 730b can alternatively include other fibers or filaments, such as carbon fibers or filaments.

The lightweight foam core is typically made from extruded polystyrene foam (XPS), but can alternately comprise expanded polystyrene foam (EPS), polyisocyanurate foam, polyurethane (PUR) foam, phenolic polymer (e.g., phenol-formaldehyde) foam, melamine polymer (e.g., melamine-formaldehyde) foam, and/or other thermoplastic or thermoset polymer known in the art that can be formed into rigid or semi-rigid foam layers. The lightweight foam core can be made of closed cell polystyrene foam to provide a water-resistant barrier (e.g., 100% waterproof).

Alternatively, the foam core may comprise an inorganic foam, such as a refractory foam material, to provide additional fire-resistance. Examples include expanded perlite (e.g., expanded spheres or microspheres), vermiculite, pumice, ceramic microspheres, hollow glass spheres, glass foam, ceramic foam, expanded silica gel, aerogel, other silicate foams, porous wollastonite, metakaolin, urea-silicate foam, SiOC/SiC foam, refractory foams, graphene, and the like. The inorganic foam core may include optional reinforcement fibers (cellulosic, basalt, E-glass, or carbon), and optional additives including hydrophobes, biocides, and phase-change or intumescent materials. The inorganic foam core can resist melting even when exposed to fire or intense heat in order for the lightweight composite panel to maintain its structural integrity.

In some embodiments, lightweight composite panels are manufactured by applying a fiber (e.g., fiberglass) mesh and cementitious or curable resin composition onto at least one surface of the inorganic foam core and causing or allowing the cementitious or curable resin composition to harden. The fiber mesh can be embedded in the cementitious or curable resin composition to enhance strength, increase toughness, and prevent cracking. In some embodiments, a fresh cementitious composition comprises mixture products of hydraulic cement, silicon dioxide powder, calcium oxide, iron oxide, plaster of Paris (gypsum hemihydrate), water-reducing agent, defoamer, styrene, and acrylic acid. The hydraulic cement typically includes Portland cement, but may also include supplementary cementitious materials (SCMs), such as ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, finely ground quartz, and the like. The fresh cementitious composition may include other components, such as natural hydraulic lime, calcium silicate, and/or expanded glass, which can increase fire and heat resistance.

The layers of fiber mesh reinforced cementitious composition are generally “thin” (e.g., typically less than about 3 mm, less than about 2.5 mm, less than about 2 mm, or less than about 1.5 mm, such as about 1 mm, or between about 0.5-3 mm, about 0.75-2.5 mm, or about 1-2 mm in cross-sectional thickness). The fiber mesh reinforced cementitious layers can be very lightweight yet waterproof and have high structural strength (i.e., high tensile and flexural strength and high toughness). The fiber mesh component is typically fiberglass fiber or glass filament mesh, but can be made of other strong fibers or filaments, such as carbon fibers or filaments. In some embodiments, fiberglass mesh is formed of an alkali-resistant material and may have nominal mesh size of 4×4 mm with a strand diameter of about 0.5-1.0 mm.

In some embodiments, the fresh cementitious composition comprises mixture products of water, hydraulic cement, silicon dioxide powder, calcium oxide, iron oxide, plaster of Paris (gypsum hemihydrate), water-reducing agent, defoamer, styrene, and acrylic acid. The fresh cementitious composition may optionally include supplementary cementitious materials (SCMs), such as ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, finely ground quartz, limestone powder, and the like. The cementitious composition may include other components, such as natural hydraulic lime, calcium silicate, and/or expanded glass, which can increase fire and heat resistance.

In the case where it is desired for lightweight composite panels to have beveled edges (e.g., to accommodate mesh tape and wall patch to join adjacent lightweight composite panels together), the fiber mesh reinforced cementitious layer can be applied before or after forming beveled edges in the form core, preferably after forming beveled edges to create a continuous fiber mesh reinforced cementitious layer across the entire surface of the lightweight composite panel.

In a more particular embodiment, the cementitious composition applied to the outer surfaces of the foam core to form fiber mesh reinforced cementitious layers of the lightweight composite panels can be formed by mixing together the following components (expressed in weight percent) to form a fresh flowable cementitious composition, which is applied to the foam core surfaces, together with fiber mesh, and then allowed to harden or cure:

	Hydraulic cement	30-50%
	Silicon dioxide	40-60%
	Calcium oxide	2-5%
	Iron oxide	0.2-1%
	Gypsum hemihydrate	3-8%
	Water-reducing agent	0.2-0.6%
	Defoamer	0.2-0.6%
	Styrene	1-2%
	Acrylic acid	1-2%
	Water	(16-20%, preferably 18.4% of
		dry ingredients above)

The hydraulic cement typically includes Portland cement clinker interground with gypsum for set control, but may also include other interground minerals, such as limestone filler (e.g., 5-10% by weight of the hydraulic cement), and optionally one or more supplementary cementitious materials (SCMs), such as ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, finely ground quartz, and the like. The silicon dioxide can be 150 mesh ground quartz sand. The water reducer can be a low-range water reducer, such as a compound of carboxylic acid grafted multi-polymer and other effective additives. The defoamer can reduce the surface tension of water, solution, suspension, etc., prevent the formation of foam, or reduce or eliminate the original foam. The main component of the defoamer can be polydimethylsiloxane (Me₃SiO(Me₂SiO)nSiMe₃) (Me=methyl). In the case where very fine SCMs (e.g., silica fume, microsilica, or metakaoline), it may be desirable to use a high range water reducer (e.g., polycarboxylate ether) to obtain good flow. The styrene and acrylic acid components, which may be a copolymer, can form a chemical bond to the extruded polystyrene foam core, in addition to the physical bond.

The components of the cementitious composition can be mixed by high-performance mixing equipment through precise batching, and then fed into a mixing barrel in sequence for high-speed dispersion and mixing, thus yielding a fresh cementitious mixture. The fresh cementitious mixture is blended in a tank to make it into liquid or plastic form. The liquid cementitious mixture is then pumped into a machine variously called a “waterfall machine,” commonly known as a “curtain coater” or enrobing “coater/machine”, which has flow control of the liquid cementitious mixture and which will apply the liquid cementitious mixture onto surfaces of an extruded polystyrene foam sheet or other material to be coated. The liquid cementitious mixture is applied like a waterfall or curtain through a blade applicator to evenly apply it to the polymer foam surfaces or other surface to be coated. The product is then cured and left to stand for approximately 7 days as usual practice. However, if ambient conditions are dry and hot, the curing period could be shortened to approximately 3-4 days.

In general, the hardened fiber mesh reinforced cementitious composition can adhere and bond strongly to the polymer or inorganic foam core to form a strong lightweight composite panel structure that does not delaminate. The bond between the cementitious layers and the foam layer is likely a combination of physical and chemical interactions. When applied to the polymer or inorganic foam layer, the liquid cementitious composition can penetrate into surface pores of the foam layer, which upon hardening of the cementitious composition, forms a strong mechanical bond. This bond can be further enhanced through the inclusion of very fine pozzolans, such as silica fume, microsilica, or metakaoline on the cementitious composition, which creates a very high strength cementitious layer and are able to fill very small micropores. The polymer components of the cementitious composition may also interact with components of the foam layer to form a type of chemical bond between the cementitious layers and the foam (e.g., polymer) layer. Regardless of how bonding occurs, it is demonstrably very strong and does not delaminate during specified use. Curable resins also adhere and bond strongly to the foam core.

In some embodiments, when manufacturing the lightweight composite panel structure, the fiberglass mesh is first laid down on a polymer (e.g., extruded polystyrene) or inorganic foam sheet. A transportation belt then transports the foam sheet with the fiberglass mesh through the waterfall machine (commonly known as a “curtain coater” or enrobing “coater/machine”), which causes the liquid cementitious mixture to flow down like a waterfall or curtain, with control of the liquid cementitious mixture flow, onto the foam sheet or other substrate. In this way, the fiberglass mesh becomes embedded in the liquid cementitious mixture and essentially floats in the middle of the cementitious mixture. In other words, a portion of the liquid cementitious mixture will be positioned between the fiberglass mesh and the foam sheet in order to directly adhere to the foam sheet, and another portion of the liquid cementitious mixture will cover and encapsulate the fiber mesh to form the top surface of the lightweight composite panel structure. The result is a layered composite structure, with an interior polymer or inorganic foam sheet, an underlying layer of cementitious composition in direct contact with the foam sheet, a fiberglass mesh in the middle, and a top layer of cementitious composition covering the fiberglass mesh.

In addition to, or instead of, a fiber mesh reinformed cementitious layer, one or both protective layers of the lightweight composite panel may comprise other materials in addition to or instead of the cementitious composition. Examples include one or more of rigid magnesium oxide material, water-resistant polymer, or a composite material comprising a resin or polymer with embedded fibers, fiber mesh, fabric, scrim, felt, or non-woven. The material forming the fibers, fiber mesh, fabric, scrim, felt, or non-woven can be selected from plant fibers, polymer fibers, and inorganic fibers (e.g., basalt, rock wool, and the like). The resin or polymer may comprise a thermoplastic or thermoset material, such as UV-cured resins, polypropylene, polycarbonate, polyethylene terephthalate, polystyrene, acrylate, methacrylate, polyurea, polyaspartic, or epoxy. Protective layers of thermoset polymer can be slightly thicker than fiber mesh reinforced cementitious layers, such as between about 1-5 mm or about 2-3 mm.

Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and an amine component. The isocyanate can be aromatic or aliphatic in nature. It can be monomer, polymer, or any variant reaction of isocyanates, quasi-prepolymer or a prepolymer. The prepolymer, or quasi-prepolymer, can be made of an amine-terminated polymer resin, or a hydroxyl-terminated polymer resin. The resin blend can include amine-terminated polymer resins and/or amine-terminated chain extenders. The resin blend may also contain additives or non-primary components, such as pigments pre-dispersed in a polyol carrier. Normally, the resin blend does not contain a catalyst. This is because the reaction between an isocyanate and amine is extremely fast and hence does not need catalysis.

The chemical structure of polyurea is as follows:

In a polyurea, alternating monomer units of isocyanates and amines react with each other to form urea linkages, as shown below.

Polyaspartic resin is a solvent-free, aliphatic amine coating material based on aspartic acid, polyaspartic acid, or polyaspartic ester, which reacts with an isocyanate to create extremely durable protective coatings with rapid cure times, excellent abrasion resistance. An example of a curable polyaspartic resin has the following reactants and final cured polymer structure:

The curable resin can be applied by spray coating while in a flowable state to one or both surfaces of the foam core and allowing it to cure and form a solid protective layer. Multiple parts of the curable resin can be mixed just prior to entering or within the nozzle used to spray coat the foam core. Where it is desired to incorporate a fiberglass mesh sheet in the polymer layer, an initial coating of curable resin can be applied to the foam core, followed by applying the fiberglass mesh sheet over the resin, followed by applying a final coating of the curable resin.

In some embodiments, the outlines of the fiberglass mesh embedded within the hardened cementitious or cured resin layer can be visible and form a grid-like texture that improves adhesion of structural and/or decorative materials thereto, such as cementitious coatings, adhesives, stucco, paint, brick veneers, masonry, stone veneers, shingles, clay tiles, metal cladding, and the like. For example, one or more stucco layers can directly adhere to the fiber mesh reinforced cementitious layer without the need for wire mesh, scratch coat, and brown coat used in conventional stucco systems. Nevertheless, it may be desirable to apply a layer of thin set mortar to cover screws, sealants, holes, or other discontinuities in the lightweight composite panels prior to applying a finished stucco layer (which can be cementitious or acrylic based).

The textured surface provided by the fiber mesh reinforced cementitious layer can facilitate adhesion of lightweight composite panels to a wall frame, such as an exterior side of a wall frame or other wall structure, in order for the lightweight composite panels to provide a substrate for application of one or more finishes. In some embodiments, an appropriate adhesive, such as construction adhesive, can be used to adhere lightweight composite panels to an exterior wall frame or structure, including studs and/or exterior sheathing, either in addition to or instead of screws or other mechanical fasteners. The use of an adhesive provides a much more continuous bond interface between the lightweight composite panels and studs or sheathing, thereby distributing the load more evenly and improving shear strength of the wall structure. The use of adhesive attachment in addition to or instead of screws can eliminate discrete attachment points, creating a more solid and continuous bond that can better resist lateral forces and improve shear strength of the wall structure.

The lightweight composite panels are typically rectangular in shape, with a constant cross sectional thickness. The lightweight composite panels can have multiple uses, including for interior walls that are exposed to moisture, providing a substrate to which tiles, stones, or other surface treatments can be applied, other interior walls (e.g., plaster coated composite panels), exterior sheathing that complements or replaces OSB panels, as a substrate for stucco, brick veneers, masonry, natural or manufactured stone, or other finishes, roofing boards that function as underlayment for shingles, roofing tiles, metal roofing sheets, wood shakes, and the like, floor underlayment, ceiling panels, and shaft liners. The lightweight composite panels can be modified for specialized uses, such as by applying a decoupling layer, drainage plane, rain screen, dimple board, factory applied dimples or dots, or bleed layer to facilitate removal of moisture between the lightweight composite panels and exterior wall or roof structures.

Advantages of the lightweight composite panels include: being lightweight (i.e., approximately ⅓ the weight of gypsum drywall and approximately ⅙ the weight of cement board); 100% waterproof as a result of the core being high density closed cell foam; high strength, high thermal insulation (i.e., proving approximately 4 times greater insulation than gypsum drywall), adequate soundproofing, and textured outer layer ideal for applying cement and glue for additional products. Further, due to the two layers of fiber reinforced cementitious composition, one on each side, a nail or screw entering both external layers can hold significant weight, substantially more weight than gypsum board.

B. Composite Wall Panels With Polymer Layer

In order for lightweight composite panels to function as an interior drywall replacement, such as where it may be desired to apply an interior finish, such as paint, wallpaper, or molding (e.g., wainscot, wood paneling, or crown molding), the lightweight composite panel functions as a core composite panel structure that is modified by forming a polymer finish layer over at least one of the fiber mesh reinforced cementitious (or other protective) layers of the core composite panel structure. The polymer finish layer can be generally white in color, although other colors are possible if desired. Additional information relating to the manufacture and use of composite wall panels with a polymer finish is disclosed in U.S. application Ser. No. 19/343,601, filed Sep. 29, 2025, which is incorporated by reference.

Composite wall panels can include a light colored (e.g., white or off white) polymer finish layer formed over at least the exterior surface of the exterior fiber mesh reinforced cementitious (or other protective) layer, and optionally the side edges, giving the composite wall panels the appearance of wallboard without paper. Because composite wall panels can include fiber mesh reinforced cementitious (or other protective) layers, along with a waterproof interior polymer or inorganic foam core, they are both waterproof and substantially stronger than conventional gypsum drywall. The composite wall panels can be used, for example, in embodiments where it is desired to construct a complete wall structure that includes two interior walls or, alternatively, an interior wall and an exterior wall made with composite wall panels to which an exterior finish is applied.

The composite wall panels include a lightweight foam core sandwiched between two fiber mesh reinforced cementitious (or other protective) layers, but with an additional polymer finish layer applied on at least one protective layer to provide a polymer finish to yield wall panels that can substitute for gypsum drywall. The polymer finish layer can be textured, sanded, painted, wallpapered, and the like, similar to the surface of conventional gypsum wallboard. However, the polymer finish layer can have a desired surface finish that eliminates the requirement to apply a finish to the paper surface of conventional gypsum drywall. The composite wall panels can be attached to wood or metal studs or other wall or ceiling structural elements using screws, nails, adhesives, or other known attachment means. The composite wall panels can also include bevels (e.g., 2 or 4) to permit placement of multiple adjacent composite wall panels, followed by application of drywall patch (taping and mudding) to hide the joints. Specialized connectors, such as washers with enlarged surfaces and penetrating prongs can be used to join adjacent composite wall panels together.

The composite wall panels include a finish layer that comprises a curable resin applied to one or both sides of the core composite panel structure and that is caused or allowed to cure. The curable resin coating layer can serve as the final surface layer for the composite wall panels. In some embodiments, the finish layer can be formed from a light-curable, UV-curable, and/or chemical-curable resin, examples of which include, but are not limited to, acrylic or methacrylic resins, aliphatic urethane acrylates, epoxy acrylates, polyester acrylates, and hybrids. An appropriate resin can be selected based on target hardness, flexibility, and adhesion properties. UV-curable resins include a photoinitiator to trigger polymerization upon UV exposure. Examples include, but are not limited to, benzoin ethers, acylphosphine oxides (e.g., diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, or TPO), and benzophenones depending on desired cure rate and depth. Alternatively, chemical cure resins known in the art can be used, such as the UV-curable resins mentioned above but which are modified to include a chemical initiator instead of, or in addition to, the photoinitiator. Examples of chemical initiators include peroxides (e.g., benzoyl peroxide), which are sometimes paired with an amine in a 2-part system, and cross-linkers.

In some embodiments, it may be desirable to apply and process the polymer finish layer in a manner that provides what is known in the industry as “level 5” finish, or “drywall finish level 5”. A level 5 finish is defined by the Gypsum Association, the trade association for drywall professionals, and is a premium finish that typically commands a much higher cost than lower level finishes. Providing a composite wall panel having a level 5 finish can eliminate the many steps and time required to prepare ordinary drywall to have a level 5 finish. This saves labor costs and time, including the time required for each coat of joint compound to dry and then be sanded.

Reference is made to FIGS. 8A-12B, which illustrate example embodiments of composite wall panels with a polymer finish. FIG. 8A illustrates the layered structure of an example composite wall panel 800. The composite wall panel 800 comprises a core composite panel structure, including a foam core 810 sandwiched between a first fiber mesh reinforced cementitious (or other protective) layer 820 and a second fiber mesh reinforced cementitious (or other protective) layer 830. A finish layer 840 is formed over the second fiber mesh reinforced cementitious (or other protective) layer 830, which forms the show side, i.e., that will be visible as the interior wall surface before applying a desired finish, such as paint and/or wallpaper. The finish layer 840 in this embodiment is shown as having a textured surface that provides the look of rough plaster.

The fiber mesh reinforced cementitious layers 820, 830 provide several advantages. The textured surface of the second fiber mesh reinforced cementitious layer 830 can enhance the bond strength of the finish layer 840 and prevent delamination. Because the first fiber mesh reinforced cementitious layer 820 does not include a finish layer it can have a textured surface that facilitates adhesion of the composite wall panel 800 to wall frame studs, ceiling joints, or other underlying structure using an adhesive or glue. In addition, the first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830 provide high strength, which permits the composite wall panel 800 to support relatively heavy loads, such as pictures, television sets, or other appliances using nails or screws, particularly if they can penetrate through both the first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830.

FIGS. 8B-8D illustrate another embodiment of a composite wall panel 800 made from a core composite panel structure with a smooth polymer finish layer formed over the exposed or show side. The composite wall panel 800 comprises the core composite panel structure, including a foam (e.g., polymer) core 810 sandwiched between first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830. A finish layer 840 is formed over the second fiber mesh reinforced cementitious (or other protective) layer 830, which forms the show side that will be visible as the interior wall surface before applying a desired final finish, such as paint or wallpaper. The finish layer 840 in this embodiment has a smooth surface finish. It will be appreciated that the finish layer 840 can have any desired surface finish, including smooth to very smooth, including having a level 5 finish, which is a substantial improvement over traditional gypsum drywall panels.

The textured surface of the second fiber mesh reinforced cementitious (or other protective) layer 830 can enhance the bond strength of the finish layer 840, which prevents delamination. The first fiber mesh reinforced cementitious (or other protective) layer 820 can have a textured surface that facilitates adhesion of the composite wall panel 800 to wall frame studs, ceiling joists, or other underlying structure. The first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830 provide high strength, which permits the composite wall panel 800 to support relatively heavy loads, such as pictures, television sets, or other appliances using nails or screws, particularly if they can penetrate through both the first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830.

FIGS. 9-11B illustrate composite wall panels 900, 1000, 1100 having beveled edges. FIG. 9 schematically illustrates a composite wall panel 900 having four beveled edges 942, one in each of the four sides, and a finish layer 940 covering the entire upper surface, beveled edges 942, and side ends 946. The finish layer 940 over the beveled edges 942 can be applied over beveled portions of a fiber mesh reinforced cementitious layer (not shown) that extend over the foam core (not shown) in the region of the beveled edges 942 to provide the beveled edges 942 with a smooth finish and additional strength.

FIG. 10A is a side cross-sectional view, and FIG. 10B is an exploded view, showing the layered structure of an embodiment of a composite wall panel 1000. As illustrated in FIG. 10A, the composite wall panel 1000 includes a foam (e.g., polymer) core 1010, a first fiber mesh reinforced cementitious (or other protective) layer 1020 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1030 on an exterior side, and a finish layer 1040 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1030. The composite wall panel 1000 includes beveled edges 1042, with a beveled portion 1012 of the foam core 1010 being partially covered by a believed portion 1032 of the second fiber mesh reinforced cementitious (or other protective) layer 1030, which in turn is covered by a beveled portion of the finish layer 1040. In this way, the beveled edges 1042 can have similar strength as the non-beveled portion of the composite wall panel 1000, which permits using nails, screws, or other fastening means to fasten the composite wall panel 1000 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1042.

FIG. 10B is an exploded view of the composite wall panel 1000 that more particularly illustrates the layered structure. The composite wall panel 1000 includes a polymer foam core 1010, a first fiber mesh reinforced cementitious (or other protective) layer 1020, which can include a first cementitious layer with embedded first fiberglass mesh (not shown), a second fiber mesh reinforced cementitious (or other protective) layer 1030, which can include a second cementitious layer with embedded second fiberglass mesh (not shown), and a finish layer 1040 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1030. The composite wall panel 1000 also includes beveled edges 1042, which includes a beveled portion 1012 of the foam core 1010 partially covered by a beveled portion 1032 of the second fiber mesh reinforced cementitious (or other protective) layer 1030, which are both covered by the beveled portion 1042 of the finish layer 1040.

FIG. 11A is a side cross-sectional view, and FIG. 11B is an exploded view, showing the layered structure of another embodiment of a composite wall panel 1100. As illustrated in FIG. 11A, the composite wall panel 1100 includes a foam (e.g., polymer) core 1110, a first fiber mesh reinforced cementitious (or other protective) layer 1120 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1130 on an exterior side, and a finish layer 1140 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1130. The composite wall panel 1100 includes beveled edges 1142, with a beveled portion 1112 of the foam core 1110 being entirely covered by a beveled portion 1132 of the second fiber mesh reinforced cementitious (or other protective) layer 1130, which in turn is covered by a beveled portion 1142 of the finish layer 1140. In this way, the beveled edges 1142 can have the same reinforcement and strength as the non-beveled portion of the composite wall panel 1100, which permits using nails, screws, or other fastening means to fasten the composite wall panel 1100 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1142.

FIG. 11B is an exploded view of the composite wall panel 1100 that more particularly illustrates the layered structure. The composite wall panel 1100 includes a foam core 1110, a first fiber mesh reinforced cementitious layer 1120, which includes a first cementitious layer 1120a with embedded first fiberglass mesh 1120b, a second fiber mesh reinforced cementitious layer 1130, which includes a second cementitious layer 1130a with embedded second fiberglass mesh 1130b, and a finish layer 1140 formed over the second fiber mesh reinforced cementitious layer 1130. The composite wall panel 1100 also includes beveled edges 1142, which includes a beveled portion of the foam core 1110 entirely covered by a beveled portion of the second fiber mesh reinforced cementitious layer 1130, which is entirely covered by a beveled portion of the finish layer 1140.

FIG. 12A illustrates two composite wall panels 1200 positioned side-by-side and abutting each other, each having a finish layer 1202a, 1202b and beveled edges 1242a, 1242b that are aligned to facilitate application of tape and drywall patch to hide the seam and join the composite wall panels 1200 together, as illustrated in FIG. 12B. FIG. 12A shows the beveled edges 1242a, 1242b covered by a portion of the finish layers 1202a, 1202b.

FIG. 12B illustrates two composite wall panels 1200 positioned side-by-side and abutting each other, with beveled edges 1234 aligned so as to permit the application of tape and drywall patch to join them together. FIG. 12B shows the beveled edges 1234 filled in with wall filler 1244 (e.g., drywall patch) such that the two composite wall panels 1200 have been joined together to yield a finished, seamless surface finish 1232. A level 5 finish can be achieved in a minimal number of steps by taping and plastering only the beveled edges 1242a, 1242b, followed by sanding the joint. Skim coating and sanding of the non-beveled portions of the finish layers 1202a, 1202b is not required if they already have a factory applied level 5 finish.

C. Composite Wall Panels With Plaster Layer

Instead of the polymer layer discussed in the previous section, lightweight composite panels can be modified by forming a polymer finish layer over at least one of the fiber mesh reinforced cementitious (or other protective) layers of the core composite panel structure. The plaster finish layer can be generally white in color, although other colors are possible if desired. Additional information relating to the manufacture and use of composite wall panels with plaster finish (“composite plaster panels”) is disclosed in U.S. patent application Ser. No. 19/306,817, filed Aug. 21, 2025, which is incorporated by reference.

The composite plaster panels are made in essentially the same way as composite wall panels with polymer layer discussed in the previous section and will have the same general structure, except that the plaster layer replaces the polymer layer. As such, FIGS. 8A-12B also illustrate embodiments of composite plaster panels with the same layered structure as composite wall panels with polymer layer, except that the plaster layer replaces the polymer layer. The plaster layer can be textured, sanded, painted, wallpapered, and the like, similar to the surface of conventional gypsum wallboard. However, the plaster layer can have a desired surface finish that eliminates the requirement to apply a finish to the paper surface of conventional gypsum drywall panels. The composite plaster panels can be attached to wood or metal studs or other wall or ceiling structural elements using screws, nails, adhesives, or other known attachment means. The composite plaster panels can also include bevels (e.g., 2 or 4) to permit placement of multiple adjacent composite plaster panels, followed by application of drywall patch (taping and mudding) to hide the joints. Specialized connectors, such as washers with enlarged surfaces and penetrating prongs can be used to join adjacent lightweight composite drywall boards together.

Reference is again made to FIGS. 8A-12B, which illustrate example embodiments of composite plaster panels that can be used to complete wall structures of the disclosure. FIG. 8A illustrates the layered structure of an example composite plaster panel 800, which comprises the basic core panel structure, including a foam core 810 sandwiched between a first fiber mesh reinforced cementitious (or other protective) layer 820 and a second fiber mesh reinforced cementitious (or other protective) layer 830. A plaster layer 840 is formed over the second fiber mesh reinforced cementitious (or other protective) layer 830, which forms the show side, i.e., that will be visible as the interior wall surface before applying a desired finish, such as paint and/or wallpaper. The plaster layer 840 in this embodiment is shown as having a textured surface that provides the look of rough plaster.

FIGS. 8B-8D illustrate another embodiment of a composite plaster panel 800 made with a smooth plaster finish layer formed over the exposed or show side. The composite plaster panel 800 comprises the core composite panel structure, including a foam (e.g., polymer) core 810 sandwiched between first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830. A plaster layer 840 is formed over the second fiber mesh reinforced cementitious (or other protective) layer 830, which forms the show side that will be visible as the interior wall surface before applying a desired final finish, such as paint or wallpaper. It will be appreciated that the plaster layer 840 can have any desired surface finish, including smooth to very smooth, including having a level 5 finish, which is a substantial improvement over traditional gypsum drywall panels.

The textured surface of the second fiber mesh reinforced cementitious (or other protective) layer 830 can enhance the bond strength of the plaster layer 840, which prevents delamination. The first fiber mesh reinforced cementitious (or other protective) layer 820 can have a textured surface that facilitates adhesion of the composite plaster panel 800 to wall frame studs, ceiling joists, or other underlying structure. The first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830 provide high strength, which permits the composite plaster panel 800 to support relatively heavy loads, such as pictures, television sets, or other appliances using nails or screws, particularly if they can penetrate through both the first and second fiber mesh reinforced cementitious (or other protective) layers 820, 830.

FIGS. 9-11B illustrate composite plaster panels 900, 1000, 1100 having beveled edges. FIG. 9 schematically illustrates a composite plaster panel 900 having four beveled edges 942, one in each of the four sides, and a plaster layer 940 covering the entire upper surface, beveled edges 942, and side ends 946. The plaster layer 940 over the beveled edges 942 can be applied over beveled portions of a fiber mesh reinforced cementitious layer (not shown) that extend over the foam core (not shown) in the region of the beveled edges 942 to provide the beveled edges 942 with a smooth finish and additional strength.

FIG. 10A is a side cross-sectional view, and FIG. 10B is an exploded view, showing the layered structure of an embodiment of a composite plaster panel 1000. As illustrated in FIG. 10A, the composite plaster panel 1000 includes a foam (e.g., polymer) core 1010, a first fiber mesh reinforced cementitious (or other protective) layer 1020 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1030 on an exterior side, and a plaster layer 1040 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1030. The composite plaster panel 1000 includes beveled edges 1042, with a beveled portion 1012 of the foam core 1010 being partially covered by a believed portion 1032 of the second fiber mesh reinforced cementitious (or other protective) layer 1030, which in turn is covered by a beveled portion of the plaster layer 1040. In this way, the beveled edges 1042 can have similar strength as the non-beveled portion of the composite plaster panel 1000, which permits using nails, screws, or other fastening means to fasten the composite wall panel 1000 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1042.

FIG. 10B is an exploded view of the composite plaster panel 1000 that more particularly illustrates the layered structure. The composite plaster panel 1000 includes a foam core 1010, a first fiber mesh reinforced cementitious (or other protective) layer 1020, which can include a first cementitious layer with embedded first fiberglass mesh (not shown), a second fiber mesh reinforced cementitious (or other protective) layer 1030, which can include a second cementitious layer with embedded second fiberglass mesh (not shown), and a finish layer 1040 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1030. The composite plaster panel 1000 also includes beveled edges 1042, which includes a beveled portion 1012 of the foam core 1010 partially covered by a beveled portion 1032 of the second fiber mesh reinforced cementitious (or other protective) layer 1030, which are both covered by the beveled portion 1042 of the plaster layer 1040.

FIG. 11A is a side cross-sectional view, and FIG. 11B is an exploded view, showing the layered structure of another embodiment of a composite plaster panel 1100. As illustrated in FIG. 11A, the composite plaster panel 1100 includes a foam (e.g., polymer) core 1110, a first fiber mesh reinforced cementitious (or other protective) layer 1120 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1130 on an exterior side, and a plaster layer 1140 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1130. The composite plaster panel 1100 includes beveled edges 1142, with a beveled portion 1112 of the foam core 1110 being entirely covered by a beveled portion 1132 of the second fiber mesh reinforced cementitious (or other protective) layer 1130, which in turn is covered by a beveled portion 1142 of the finish layer 1140. In this way, the beveled edges 1142 can have the same reinforcement and strength as the non-beveled portion of the composite plaster panel 1100, which permits using nails, screws, or other fastening means to fasten the composite plaster panel 1100 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1142.

FIG. 11B is an exploded view of the composite plaster panel 1100 that more particularly illustrates the layered structure. The composite plaster panel 1100 includes a foam core 1110, a first fiber mesh reinforced cementitious layer 1120, which includes a first cementitious layer 1120a with embedded first fiberglass mesh 1120b, a second fiber mesh reinforced cementitious layer 1130, which includes a second cementitious layer 1130a with embedded second fiberglass mesh 1130b, and a finish layer 1140 formed over the second fiber mesh reinforced cementitious layer 1130. The composite plaster panel 1100 also includes beveled edges 1142, which includes a beveled portion of the foam core 1110 entirely covered by a beveled portion of the second fiber mesh reinforced cementitious layer 1130, which is entirely covered by a beveled portion of the plaster layer 1140.

FIG. 12A illustrates two composite plaster panels 1200 positioned side-by-side and abutting each other, each having a plaster layer 1202a, 1202b and beveled edges 1242a, 1242b that are aligned to facilitate application of tape and drywall patch to hide the seam and join the composite plaster panels 1200 together, as illustrated in FIG. 12B. FIG. 12A shows the beveled edges 1242a, 1242b covered by a portion of the plaster layers 1202a, 1202b.

FIG. 12B illustrates two composite plaster panels 1200 positioned side-by-side and abutting each other, with beveled edges 1234 aligned so as to permit the application of tape and drywall patch to join them together. FIG. 12B shows the beveled edges 1234 filled in with wall filler 1244 (e.g., drywall patch) such that the two composite plaster panels 1200 have been joined together to yield a finished, seamless surface finish 1232. A level 5 finish can be achieved in a minimal number of steps by taping and plastering only the beveled edges 1242a, 1242b, followed by sanding the joint. Skim coating and sanding of the non-beveled portions of the plaster layers 1202a, 1202b is not required if they already have a factory applied level 5 finish.

In some embodiments, a fresh plaster composition used to form the plaster layer comprises mixture products of water, hydraulic cement, preferably white cement, calcium carbonate, aluminum oxide, silicon dioxide, cellulose ether, and latex. The fresh plaster composition may optionally include supplementary cementitious materials (SCMs), such as ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, finely ground quartz, limestone powder, and the like. The cementitious composition may include other components, such as natural hydraulic lime, calcium silicate, and/or expanded glass, which can increase fire and heat resistance.

In a more particular embodiment, the fresh plaster composition used to form one or more plaster layers can be formed by mixing together the following components (expressed in weight percent) to form a fresh, flowable plaster composition, which is applied to one or both sides of the core composite panel structure, and then allowed to harden or cure:

Hydraulic cement	30-50%
Calcium carbonate	40-70%
Aluminum oxide (Al2O3)	1-3%
Silicon dioxide	4-8%
Calcium oxide	2-5%
Hydroxypropyl methylcellulose	0.2-06%
Latex powder	2-4%
Water	(0.5 to 1.5, or 0.75 to 1.25, or 1 part
	water per 2.5 parts of dry ingredients)

The hydraulic cement typically includes Portland cement, preferably white cement for aesthetic reasons, but may also include supplementary cementitious materials (SCMs), such as ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, finely ground quartz, and the like. The Portland cement comprises ground cement clinker interground with gypsum for set control and limestone as a filler. For aesthetic reasons, SCMs, when included, are preferably white or light colored. The silicon dioxide can be 150 mesh ground quartz sand. The latex powder can be redispersible 558 latex, which can be an ethylene/vinyl acetate copolymer, vinyl acetate/versatate copolymer, acrylic copolymer, etc. The latex powder can improve adhesion of the plaster layer to a cementitious layer.

The dry components of the plaster composition, known euphemistically as “putty powder”, can be dry mixed in a mixer to form an evenly mixed dry blend. Then the water is added to the mixture to form a fresh flowable plaster composition that can be sprayed. A spray gun is used to apply the fresh plaster composition to the fiber mesh reinforced cementitious layer of a basic lightweight composite panel (e.g., with or without beveled edges). The amount of plaster composition applied should be sufficient to cover the fiber mesh reinforced cementitious layer so that the grid-like texture is no longer visible, forming a smooth surface (or surface having a desired texture). The plaster composition is then allowed to cure for 7 days to form a hardened surface, which can be polished if desired to yield a smooth surface.

In some embodiments it may be desirable to cut the beveled edges to a width of about 1.5 inches (e.g., 1-2 inches, or 1.25-1.75 inches). If any portion of the composite plaster panels includes exposed expanded polystyrene foam, a primer can be used to cover the exposed polystyrene foam to enhance strength and improved the bond of drywall patch to the composite plaster panels.

D. Laminated Composite Wall Panels

Another version of lightweight composite panel that can be used to form an interior wall of a complete wall system includes a fiber-based sheet laminated over one or both sides of the core composite panel structure to yield a laminated composite wall panel. An intermediate polymer layer can optionally be formed over one or both sides of the core composite panel structure to form a smooth surface to which the fiber-based sheet layer can be applied. In some embodiments, the intermediate polymer layer can be the same polymer materials used above to form composite wall panels with polymer finish layer. The fiber-based sheet layer can be generally white or off white in color, although other colors are possible if desired. Additional information relating to the manufacture and use of laminated composite wall panels is disclosed in U.S. patent application Ser. No. 19/343,312, filed Sep. 29, 2025, which is incorporated by reference.

Laminated composite wall panels include a light colored (e.g., white or off white) fiber-based sheet layer formed over at least the exterior surface of the exterior fiber mesh reinforced cementitious (or other protective) layer, and optionally the side edges, giving the laminated composite wall panels the appearance of traditional wallboard but without a water-sensitive gypsum core. Because laminated composite wall panels can include fiber mesh reinforced cementitious (or other protective) layers, along with a waterproof interior polymer foam core, they are both waterproof and substantially stronger than conventional gypsum drywall. Moreover, the core composite panel structure is waterproof, providing extra safety if the laminated composite wall panels are inadvertently exposed to water. Even if the fiber-based sheet is damaged, the structural integrity of the composite wall panel structure is maintained and not compromised like traditional gypsum wallboard. Moreover, the fiber-based sheet layer can include a waterproofing material on or in the fiber-based sheet to protect it from moisture damage and absorption of deleterious substances and contaminants.

The fiber-based sheet layer may include any fiber-based sheet material, including but not limited to, paper, fabrics, wovens, non-wovens, and the like. The fibers in the fiber-based sheet layer may include organic and/or inorganic fibers or filaments. Thus, the term “fiber” may include fibers and/or filaments. Examples of organic fibers include natural fibers and synthetic fibers or filaments that are used to make paper, fabrics, wovens, non-wovens, and the like. Examples of inorganic fibers include glass fibers or filaments, carbon fibers or filaments, and the like.

The laminated composite wall panels include a lightweight foam core sandwiched between two fiber mesh reinforced cementitious (or other protective) layers, but with an additional fiber-based sheet applied on at least one protective layer to provide a fiber-based sheet finish to yield wall panels that can substitute for gypsum drywall. The fiber-based sheet layer can be skim-coated with plaster (e.g., drywall patch), painted, wallpapered, and the like, similar to the surface of conventional gypsum wallboard. The laminated composite wall panels can be attached to wood or metal studs or other wall or ceiling structural elements using screws, nails, adhesives, or other known attachment means. The laminated composite wall panels can also include bevels (e.g., 2 or 4) to permit placement of multiple adjacent laminated composite wall panels, followed by application of drywall patch (taping and mudding) to hide the joints. Specialized connectors, such as washers with enlarged surfaces and penetrating prongs can be used to join adjacent laminated composite wall panels together.

When included, the intermediate polymer layer beneath the fiber-based sheet layer can be formed from a light-curable, UV-curable, and/or chemical-curable resin, examples of which include, but are not limited to, acrylic or methacrylic resins, aliphatic urethane acrylates, epoxy acrylates, polyester acrylates, and hybrids. An appropriate resin can be selected based on target hardness, flexibility, and adhesion properties. UV-curable resins include a photoinitiator to trigger polymerization upon UV exposure. Examples include, but are not limited to, benzoin ethers, acylphosphine oxides (e.g., diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, or TPO), and benzophenones depending on desired cure rate and depth. Alternatively, chemical cure resins known in the art can be used, such as the UV-curable resins mentioned above but which are modified to include a chemical initiator instead of, or in addition to, the photoinitiator. Examples of chemical initiators include peroxides (e.g., benzoyl peroxide), which are sometimes paired with an amine in a 2-part system, and cross-linkers.

FIG. 13A is a side cross-sectional view, and FIG. 13B is an exploded view, showing the layered structure of an embodiment of a laminated composite wall panel 1300. As illustrated in FIG. 13A, the laminated composite wall panel 800 includes a foam (e.g., polymer) core 1310, a first fiber mesh reinforced cementitious (or other protective) layer 1320 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1330 on an exterior side, and a fiber-based sheet layer and optional intermediate polymer layer 1340 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1330 and covering the sides and an outer perimeter portion of the first fiber mesh reinforced cementitious (or other protective) layer 1320. The laminated composite wall panel 1300 includes beveled edges 1342, with a beveled portion 1312 of the foam core 1310 being entirely covered by a beveled portion 1332 of the second fiber mesh reinforced cementitious (or other protective) layer 1330, which in turn is covered by a beveled portion 1342 of the fiber-based sheet layer and optional intermediate polymer layer 1340. In this way, the beveled edges 1342 can have the same reinforcement and strength as the non-beveled portion of the laminated composite wall panel 1300, which permits using nails, screws, or other fastening means to fasten the laminated composite wall panel 1300 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1342.

FIG. 13B is an exploded view of the laminated composite wall panel 1300 that more particularly illustrates the layered structure. The laminated composite wall panel 1300 includes a foam core 1310, a first fiber mesh reinforced cementitious layer 1320, which includes a first cementitious layer 1320a with embedded first fiberglass mesh 1320b, a second fiber mesh reinforced cementitious layer 1330, which includes a second cementitious layer 1330a with embedded second fiberglass mesh 1330b, and a fiber-based sheet layer and optional intermediate polymer layer 1340 formed over the second fiber mesh reinforced cementitious layer 1330 and covering the sides and an outer perimeter portion of the first fiber mesh reinforced cementitious (or other protective) layer 1320. The laminated composite wall panel 1300 also includes beveled edges 1342, which includes a beveled portion of the foam core 1310 entirely covered by a beveled portion 1332 of the second fiber mesh reinforced cementitious layer 1330, which is entirely covered by a beveled portion 1342 of the fiber-based sheet layer and optional intermediate polymer layer 1340.

FIG. 13C illustrates another example embodiment of a laminated composite wall panel 1300 with a fiber-based sheet layer 1302 and two beveled edges 1304. FIG. 13D illustrates an example laminated composite wall panel 1320 with a fiber-based sheet layer 1322 but no beveled edges.

FIGS. 12A-12B, discussed above relative to composite wall panels having a polymer or plaster finish, is also helpful in illustrating how laminated composite wall panels with beveled edges can be joined together. FIG. 12A illustrates two laminated composite wall panels 1200 positioned side-by-side and abutting each other, each having a fiber-based sheet layer 1202a, 1202b and beveled edges 1242a, 1242b that are aligned to facilitate application of tape and drywall patch to hide the seam and join the laminated composite wall panels 1200 together, as illustrated in FIG. 12B. FIG. 12A shows the beveled edges 1242a, 1242b covered by a portion of the fiber-based sheet layers 1202a, 1202b.

FIG. 12B illustrates two laminated composite wall panels 1200 positioned side-by-side and abutting each other, with beveled edges 1234 aligned so as to permit the application of tape and drywall patch to join them together. FIG. 12B shows the beveled edges 1234 filled in with wall filler 1244 (e.g., drywall patch) such that the two laminated composite wall panels 1200 have been joined together to yield a finished, seamless surface finish.

E. Lightweight Composite Panels With Drainage Layer

As discussed herein, lightweight composite panels can be used to form one or two exterior walls of a wall structure. In some cases, particularly where lightweight composite panels used to make an exterior wall are fastened over OSB panels or other wooden sheathing, it may be desirable to incorporate a drainage layer between the lightweight composite panels and wooden sheathing. The drainage layer facilitates the removal of liquid water and water vapor from between the sheathing and lightweight composite panels to prevent damage to the sheathing and possible mold growth. Additional information relating to the manufacture and use of composite wall panels with drainage layer is disclosed in U.S. application Ser. No. 19/306,826, filed Aug. 21, 2025, which is incorporated by reference.

The core composite panel structure is modified by attaching a drainage layer (e.g., polymer uncoupling membrane, embossment, drainage plane, rain screen, dimple board, factory applied raised dimples or dots, or bleed layer (collectively “drainage layer”) to an interior-facing surface that is designed to face a wall or roofing frame. The drainage layer provides a built-in drainage plane by providing spaced contact points that create a capillary break, enabling vertical drainage of incidental moisture. The drainage layer provides gaps and channels between the core composite panel structure and the underlying wall or roof structure (e.g., studs, trusses, and/or OSB sheathing) to permit moisture to collect and drain and/or evaporate, thereby protecting outer surface finishes and preventing or minimizing formation of mold, mildew, and structural damage of the underlying wall or roof structure and/or exterior finish, such as by freeze-thaw cycles, delamination, or other water-related issues.

The drainage layer can be applied to the core composite panel structure using waterproof adhesive or directly adhered to the cementitious composition or thermoset polymer used to make the protective layer on the interior side of the core composite panel structure. In some embodiments, the protective layer on the side of the core composite structure that is configured to be placed against sheathing or other structural elements may comprise a waterproof (e.g., polymer) material that is pre-formed or molded to include gaps and channels that can function as a drainage layer to facilitate moisture removal. In other embodiments, a built-in drainage plane can be formed by applying a field of raised adhesive dimples to the back surfaces of the lightweight composite building panel.

FIGS. 14A and 14B illustrate embodiments of example lightweight composite building panels 1400a, 1400b for exterior use that includes a core composite panel structure 1402 and incorporated drainage layers 1404a, 1404b made of polymer or other material that provides a pathway for removal of moisture from between the lightweight composite building panels 1400a, 1400b and sheathing or other structural elements of an exterior wall or roof structure (not shown). The drainage layer 1404a, 1404b can be called or referred to as an uncoupling membrane, drainage plane, rain screen, dimple board, or bleed layer. For purposes of this disclosure, they are collectively referred to as a “drainage layer”. The drainage layers 1404a, 1404b include physical gaps to promote drainage and removal of moisture that might otherwise collect between the lightweight composite building panels 300a, 300b and the underlying wall or roof structure to which they are attached.

The drainage layers 1404a, 1404b can be attached to a surface of the core composite panel structures 1402a, 1402b using adhesives known in the art. In some embodiments, the drainage layers 1404a, 1404b can be adhered to the core composite panel structures 1402a, 1402b using a standard polymer modified mortar, such as the cementitious composition used to form the outer surface layers of the core composite panel structures 1402a, 1402b. In some embodiments, the protective layer on the side of the core composite panel structure 1402 that is configured to be placed against sheathing or other structural elements may comprise a waterproof (e.g., polymer) material that is pre-formed or molded to include gaps and channels that can function as a drainage layer to facilitate moisture removal.

The surface of the lightweight composite building panels 1400a, 1400b opposite the drainage layers 1404a, 1404b can be a fiber mesh reinforced cementitious layer that can be used to apply a desired exterior surface finish, such as stucco, brick veneers, masonry, tiles, stone veneers, shingles, and the like. The lightweight composite building panels 1400a, 1400b provide a waterproof exterior surface that also provides for moisture removal, such as to prevent growth of mold and mildew or structural damage to the underlying wall or roof structure.

The drainage layer can alternatively comprise factory-applied dimples to the back side of a lightweight composite building panel. A built-in drainage plane can be made by applying a field of raised adhesive dimples to the back surface of each lightweight composite building panel. These spaced contact points create a capillary break, enabling vertical drainage of incidental moisture. This method eliminates the need for separately installed rainscreen mats or drainage layers (either in the field or in the factory) while maintaining full panel-sheathing contact.

In a controlled factory setting, automated metered dispensers are configured to apply a substantially uniform grid of polymer-based dots or beads to the panel back. Each bead can be cured to a consistent height of about 1/16 inch to ¼ inch, maintaining an air gap between the panel and substrate.

FIGS. 14C-14E illustrate exterior building elements or finishes 1400 attached to an underlying wall 1402 of a building. They illustrate how a gap 1404 is provided between the exterior building elements or finishes 1400 and the underlying building wall 1402. This gap 1404 permits moisture that may have entered this region to be drained and/or evaporated away from the underlying building wall 1402. FIG. 14C, in particular, illustrates how condensed liquid water 1406 can drain from the bottom of the gap 1404 and how water vapor 1408 can vent from the top of the gap 1404. FIG. 14D illustrates how water that may penetrate through an exterior finish 1400 can drain though the gap 1404. FIG. 14E illustrates how water that may penetrate through an exterior finish 1400 can drain though the gap 1404 and/or how water vapor can diffuse through the exterior finish 1400.

III. Wall Structures

FIGS. 15A and 15B illustrate an example wall structure 1500 that includes a wall frame comprising metal studs 1502, a first lightweight composite panel 1504 fastened to the metal studs 1202 on a first side of the wall frame, OSB sheathing 1506 fastened to the metal studs 1202 and forming a second side of the wall frame, and a second lightweight composite panel 1508 fastened to the OSB sheathing 1506. A stucco finish 1510 is applied directly to an exterior side of the second lightweight composite panel 1508 to form an exterior wall of the wall structure 1500. The first lightweight composite panel 1504 comprises a lightweight composite panel, e.g., which can have a polymer, plaster, or paper layer on the show surface, which has or can include a desired finish, such as paint, wallpaper, molding, and the like, to form an interior wall of the wall structure 1500. The first and second lightweight composite panels 1504, 1508 can be fastened to the studs 1502 or OSB sheathing 1506 of the wall frame 1502 using any fastening means known in the art, such as wood screws, self-drilling/tapping metal screws, rivets, nails, construction adhesive, and combinations thereof.

FIGS. 16A-16D are models of various complete wall structures in which lightweight composite panels fully enclose the first and second sides of the wall frame. FIG. 16A is a first model of a complete wall structure 1600 according to the disclosure. The complete wall structure 1600 includes a wall frame 1602 comprising wooden studs 1604 and OSB sheathing 1606 fastened to one side of the studs 1604. A first lightweight composite panel 1608 is attached to the wooden studs 1604 on a first side of the wall frame 1602 by screws and enlarged washers (not shown). The first lightweight composite panel 1608 is a modified lightweight composite panel having a polymer, plaster, or paper layer on the show side, similar to any of the lightweight composite panels illustrated in FIGS. 8A-13D, so as to form an interior wall of the complete wall structure 1600. Although not shown, the polymer, plaster, or paper layer on the show side of the first lightweight composite panel 1608 can have or receive a surface finish, such as one or more of paint, wallpaper, or molding (e.g., wainscot, wood paneling, or crown molding) to form a finished interior wall.

The complete wall structure 1600 further includes a pair of second lightweight composite panels 1612a, 1612b fastened to the OSB sheathing 1606 on the side opposite the first lightweight composition panel 1608 using a plurality of exterior corrosion-resistant screws 1616 and enlarged washers 1618 to form an exterior wall of the complete wall structure 1600. Third and fourth lightweight composite panels 1612c, 1612d are fastened to the left and right ends of the wall frame 1602 using screws and enlarged washers (not shown) so that the wall frame 1602 is enclosed by lightweight composite panels on all four sides. The enlarged washers 1618 have penetrating prongs (not shown) embedded in the lightweight composite panels 1608, 1612 to prevent rotation of the washers 1618, increase gripping force, and limit how far the enlarged washers 1618 can be driven into the lightweight composite panels. The enlarged washers 1618 and penetrating prongs prevent the screws 1616 from breaking through, while allowing slight compression of, the exterior fiber mesh reinforced cementitious (or other protective) layer of the first, second, third, and fourth lightweight composite panels 1608, 1612 to prevent damage thereto while ensuring good fixation of the panels to the wall frame 1602.

With reference to the exterior wall portion of the wall structure 1600, a layer of water-proofing black paper 1610 is positioned between the OSB sheathing 1606 and the second lightweight composite panels 1612a, 1612b to protect the OSB sheathing 1606 from moisture ingress (i.e., in the unlikely event moisture would somehow collect beneath the otherwise waterproof lightweight composite panels 1612a, 1612b). Protecting the OSB sheathing 1606 from moisture prevents mold growth in and structural damage to the OSB sheathing 1606. A stucco finish 1626 is applied to the exterior fiber mesh reinforced cementitious (or other protective) layers of the second, third, and fourth lightweight composite panels 1612a, 1612b, 1612c, 1612d to form an exterior surface finish.

A vertical concourse of screws 1616 and enlarged washers 1618 are used to interconnect the adjacent second lightweight composite panels 1612a, 1612b fastened to the OSB sheathing 1606. A vertical strip of fiber mesh tape 1620 is placed over the screws 1616 and enlarged washers 1618 and a portion of the exterior fiber reinforced cementitious (or other protective) layers of the second lightweight composite panels 1312a, 1312b, followed by application of a vertical strip of an appropriate seam coat (e.g., thin set mortar or fine-sanded stucco) 1624 over the fiber mesh tape 1620, screws 1616 and enlarged washers 1618, and a portion of the exterior fiber reinforced cementitious (or other protective) layers to further tie the second lightweight composite panels 1612a, 1612b together. The seam coat provides a smooth surface and further helps prevent separation and potential formation of cracks in the stucco finish 1626 placed over the joint between the adjacent lightweight composite panels 1612a, 1612b. The same or different material used for the seam coat 1624 can be applied as a patch 1622 over screws 1616 and enlarged washers 1618 in other regions to form a smooth surface over which the stucco finish 1626 can be applied.

The complete wall structure 1600 includes first and second corners at the interfaces between the first lightweight composite panel 1608 and third and fourth lightweight composite panels 1612c, 1612d positioned at 90° angles. The first corner is illustrated as being tied together and protected by a strip of fiber mesh 1614a and a corner layer of an appropriate seam coat (not shown, e.g., thin set mortar or fine-sanded stucco) in which the fiber mesh fiber mesh 1614a is embedded. The second corner is illustrated as being tied together and protected by a rigid or semi-rigid corner bend 1614b, which can be made of metal or polymer, such as polyvinyl chloride (PVC), and a second corner layer of seam coat 1625 in which the corner bend 1614b is embedded. It will be understood that the fiber mesh 1614a and corner bend 1614b are alternative embodiments and need not be included in the same wall structure. Rather, some embodiments may use the fiber mesh 1614a for simplicity and cost and other embodiments may use the corner bend corner bend 1614b (e.g., to provide greater protection against mechanical damage caused by blunt force to the corners). The stucco finish 1626 (cement- or acrylic-based) is applied over the exterior-facing fiber mesh reinforced cementitious layer and the patch of seam coat 1625. A primer is typically not required when using acrylic-based stucco, although one can be used if desired.

FIG. 16B is a second model of a complete wall structure 1600 according to the disclosure. The complete wall structure 1600 includes a wall frame 1602 comprising wooden studs 1604 and OSB sheathing 1606 fastened to a first side of the studs 1604. The OSB sheathing 1606 can be covered with a lightweight composite panel (not shown) to form an interior wall, or it can be covered with a lightweight composite panel (not shown) to which an exterior finish is applied to form an exterior wall. Alternatively, the OSB sheathing 1606 can be omitted and replaced with lightweight composite panels (not shown) as sheathing to form a shear wall. A second layer of lightweight composite panels can be placed over the first sheathing layer of lightweight composite panels. The lightweight composite panel on the interior side of the wall structure 1600 can have a polymer, plaster, or paper layer, similar to any of the lightweight composite panels illustrated in FIGS. 8A-13D. A surface finish can be applied to the lightweight composite panel (not shown) that covers or replaces the OSB sheathing 1606, such as one or more of paint, wallpaper, or molding (e.g., wainscot, wood paneling, or crown molding) to form a finished interior wall.

A first lightweight composition panel 1610a is attached to the wooden studs 1404 on a second side of the wall frame 1602 opposite the first side by screws 1616 and enlarged washers 1618. Second and third lightweight composite panels 1610b, 1610c are fastened to the ends of the wall frame 1602 using screws and enlarged washers (not shown) so that the wall frame 1602 is enclosed by lightweight composite panels and the OSB sheathing 1606 on all four sides. The enlarged washers 1618 have penetrating prongs (not shown) embedded in the lightweight composite panels 1610 to prevent rotation of the washers 1618, increase gripping force, and limit how far the enlarged washers 1618 can be driven into the lightweight composite panels. The enlarged washers 1618 and penetrating prongs prevent the screws 1616 from breaking through, while allowing slight compression of, the exterior fiber mesh reinforced cementitious (or other protective) layer of the lightweight composite panels 1610 to prevent damage thereto while ensuring good fixation of the panels 1610 to the wall frame 1602.

The complete wall structure 1600 includes first and second corners at the interfaces between the first lightweight composite panel 1610a and the second and third lightweight composite panels 1610b, 1610c positioned at 90° angles. The first corner is illustrated as being tied together and protected by a rigid or semi-rigid corner bend 1614a, which can be made of metal or polymer, such as polyvinyl chloride (PVC), and a first corner layer of seam coat 1625a (e.g., thin set mortar or fine-sanded stucco) in which the corner bend 1614a is embedded. The second corner is illustrated as being tied together and protected by a strip of fiber mesh 1614b and a second corner layer of seam coat 1625b in which the fiber mesh fiber mesh 1614b is embedded. It will be understood that the corner bend 1614a and fiber mesh 1614b are alternative embodiments and need not be included in the same wall structure. Rather, some embodiments may use the fiber mesh 1614b (e.g., for simplicity and cost) and other embodiments may use the corner bend corner bend 1614a (e.g., to provide greater protection against mechanical damage caused by blunt force to the corners). The same or different material used for the seam coat 1625 can be applied over the screws 1616 and enlarged washers 1618 to form a smooth surface over which a stucco finish 1626 can be applied. The stucco finish 1626 (cement- or acrylic-based) is applied over exterior-facing fiber mesh reinforced cementitious (or other protective) layers of the first, second, and third lightweight composite panels 1610a, 1610b, 1610c and the seam coats 1625. A primer is typically not required when using acrylic-based stucco, although one can be used if desired.

FIG. 16C is a third model of a complete wall structure 1600 according to the disclosure, which includes a wall frame 1602 comprising wooden studs 1604 and plywood sheathing 1606 fastened to a first side of the studs 1604. The plywood sheathing 1606 can be covered with a lightweight composite panel with interior show layer (not shown) to form an interior wall, or it can be covered with a lightweight composite panel (not shown) to which an exterior finish is or can be applied to form an exterior wall. Alternatively, the plywood sheathing 1606 may be omitted and replaced with a lightweight composite panel (not shown) as sheathing to form a shear wall. A surface finish can be applied to the lightweight composite panel with show layer, such as one or more of paint, wallpaper, or molding (e.g., wainscot, wood paneling, or crown molding) to form a finished interior wall.

A lightweight composite panel 1610 is attached to the wooden studs 1604 on a second side of the wall frame 1602 opposite the first side by screws (not shown) and enlarged washers (not shown). The enlarged washers can have penetrating prongs (not shown) embedded in the lightweight composite panel 1610 to prevent rotation of the washers, increase gripping force, and limit how far the enlarged washers can be driven into the lightweight composite panel 1610. The enlarged washers and penetrating prongs prevent the screws from breaking through, while allowing slight compression of, the exterior fiber mesh reinforced cementitious layer of the lightweight composite panel 1610 to prevent damage thereto while ensuring good fixation of the panel 1610 to the wall frame 1602.

FIG. 16D is a fourth model of a complete wall structure 1600 according to the disclosure. The complete wall structure 1600 includes a wall frame 1602 comprising wooden studs 1604 and plywood or OSB sheathing 1606 fastened to a first side of the studs 1604. The plywood or OSB sheathing 1606 can be covered with a lightweight composite panel (not shown) to form an interior wall to which tiles, stone, or other interior finish is or can be applied, or it can be covered with a lightweight composite panel (not shown) to which an exterior finish is or can be applied to form an exterior wall. Alternatively, the plywood or OSB sheathing 1606 may be omitted and replaced with a lightweight composite panel (not shown) as sheathing to form a shear wall. A second layer of lightweight composite panels can be placed over the first sheathing layer of lightweight composite panels.

A pair of lightweight composite panels 1610a, 1610b having first and second polymer or plaster show layers 1612a, 1612b are attached to the wooden studs 1604 on a second side of the wall frame 1602 opposite the first side by screws 1616. The lightweight composite panels 1610a, 1610b are connected together by a strip of fiber mesh tape 1620, which is thereafter covered with a seam coat 1622, which can be a skim coat of joint compound or plaster to form a smooth surface over which one or more layers of paint 1626 are applied. The joint compound or plaster can also cover any other exposed screws 1616 and screw holes in the lightweight composite drywall boards 1610a, 1610b to form a smooth surface over which the one or more layers of paint 1626 are applied.

FIGS. 17-21 schematically illustrate exterior sides of wall structures with various exterior finishes to illustrate additional aspects of complete wall structures that can be made according to the disclosure. FIG. 17 is a model that illustrates and compares two exterior stucco finishes, including an example stucco system 1700 that is made using a lightweight composite panel 1720 according to the disclosure and a traditional stucco system 1750 that includes multiple layers of various materials. The example stucco system 1700 of the disclosure and the traditional stucco system 1750 are both formed over OSB panel 1710, which is an example of wall sheathing of an exterior wall of a wall structure. A waterproof polymer membrane 1712 is attached over the OSB sheathing 1710 to protect it from moisture and optionally create an air barrier over joints or seams between adjacent OSB panels 1710. Alternatively, the OSB sheathing 1710 can be replaced with lightweight composite panels as sheathing, which can be covered by a second layer of lightweight composite panels to which a stucco finish is applied. Alternatively, the stucco finish can be applied to the lightweight composite panels used as sheathing without a second layer.

The example stucco system 1700 of the disclosure includes a lightweight composite panel 1720, which includes an exterior-facing fiber mesh reinforced cementitious (or other protective) layer 1722 as a bonding substrate. The lightweight composite panel 1720 is fastened to the OSB panel 1710 by screws 1724. Two of the screws 1724 are shown covered by patches of a seam coat (e.g., thin set mortar or fine-sanded stucco) 1726 to create a smooth surface (although it is understood that all screws or other fasteners can be covered with the seam coat 1726). A stucco finish 1728 is applied over the fiber mesh reinforced cementitious (or other protective) layer 1722 and patches of seam coat 1726. Both cement-based stucco and acrylic stucco can readily adhere directly to the fiber mesh reinforced cementitious (or other protective) layer 1722 and seam coat 1726.

The traditional stucco system 1750, by comparison, includes a layer of black backing paper 1752 for additional moisture protection applied over the waterproof polymer membrane 1712. The black backing paper 1752 can be attached to the OSB panel 1710 by means of staples or nails (not shown). Wire lath 1754 is applied over the black backing paper 1752 and fastened to the OSB panel 1710 by nails or screws 1756. A scratch coat 1758 made from sand, cement, water, and optional components is applied over the wire lath 1754 using a trowel or sprayer. The wire lath 1754 is embedded within the scratch coat 1758 to mechanically retain the scratch coat 1758 against the black backing paper 1752 (as there is no bond-physical or chemical-between the scratch coat 1758 and black backing paper 1752. A scarifier tool is used to form horizontal ridges and troughs in the scratch coat 1758 while the scratch coat 1758 is in a plastic state. After the scratch coat 1758 has hardened, typically after at least one day, a brown coat 1760 made from sand, cement, water, and optional components is applied over the scratch coat 1758 using a trowel or sprayer to form a smooth surface. The horizontal ridges and troughs in the scratch coat 1758 create a good mechanical bond between the brown coat 1760 and the scratch coat 1758. Finally, after the brown coat 1760 has hardened, typically after at least one day, a stucco finish 1762 is applied over the brown coat 1760. Cement-based stucco can adhere directly to the brown coat 1760. In the case where the stucco layer 1728 is acrylic-based stucco, a primer (not shown) is typically applied over the brown coat 1760 to improve adhesion. Ultimately, the only thing holding the entirety of the traditional stucco system 1750 to the OSB panels 1710 are the nails or screws 1756.

FIGS. 18A and 18B schematically illustrate an embodiment of an exterior stucco system 1800 made using a lightweight composite panel 1840 as the substrate for the stucco finish. FIG. 18A shows an exploded view of the exterior stucco system 1800, and FIG. 18B shows an assembled view of the exterior stucco system 1800. The exterior stucco system 1800 includes an OSB panel 1810 as wall sheathing and a waterproof polymer membrane 1820 (e.g., house wrap) applied over the OSB panel 1810 to protect it from moisture and optionally form an air barrier over seams or joints between adjacent OSB panels 1810. A water drainage layer 1830 is positioned over the waterproof polymer membrane 1820 to provide a pathway of escape for any moisture that may collect between the lightweight composite panel 1840 and the waterproof polymer membrane 1820. The drainage layer 1830 facilitates drainage and removal of water by the force of gravity and/or evaporation. The lightweight composite panel 1840 can be fastened to the OSB panel 1810 using screws, nails, rivets, or other fasteners known in the art. A stucco finish 1860 (cement-based or acrylic-based) is applied over an exterior-facing fiber mesh reinforced cementitious (or other protective) layer 1850 of the lightweight composite panel 1840. Indentations or other surface defects caused by screws or other mechanical fasteners (not shown) can be covered by patches of seam coat (not shown) to form a more uniform surface over which the stucco finish 1860 is applied.

In some embodiments, the OSB panel 1810 can be covered with a lightweight composite panel with factory applied drainage layer, such as what is described relative to FIGS. 14A and 14B above and which are disclosed in more detail in U.S. application Ser. No. 19/306,826, filed Aug. 21, 2025, which is incorporated by reference. In other embodiments, the OSB panel 1810 can be omitted and replaced with a lightweight composited panel as sheathing, as disclosed in U.S. application Ser. No. 19/306,800, filed Aug. 21, 2025, which is incorporated by reference. The lightweight composite panel sheathing can be covered with a second layer of lightweight composite panels to which an exterior finish is applied. Alternatively, an exterior finish can be applied directly to the lightweight composite panel sheathing.

FIGS. 19A and 19B show different perspective views of a model of an example stucco system 1900 for use in making an exterior wall of a complete wall structure according to the disclosure. The example stucco system 1900 includes a wall frame 1902 formed using studs 1904 and an OSB panel 1906. A first lightweight composite panel 1908a forming an exterior wall surface is fastened to the OSB panel 1906 using a plurality of screws 1910. Second and third lightweight composite panels 1908b, 1908c are applied to the ends of the wall frame 1902. A patch of seam coat (e.g., thin set mortar or fine-sanded stucco) 1918 is shown applied over one of the screws 1910 and a portion of an exterior-facing fiber mesh reinforced cementitious layer 1916 to form a more uniform surface to which a stucco finish 1920 can be applied.

The second and third lightweight composite panels 1908b, 1908c are positioned at 90° angles relative to the first lightweight composite panel 1908a to form first and second corners. The first corner is protected by fiber mesh 1912 shown partially embedded in a first corner layer of seam coat 1918 (e.g., thin set mortar or fine-sanded stucco). The second corner is protected by a rigid or semi-rigid corner bend 1914 attached by screws (FIG. 19B), which can be made of metal or polymer, such as polyvinyl chloride (PVC), and shown partially embedded in a second corner layer of seam coat 1918. It will be understood that the fiber mesh 1912 and corner bend 1914 are alternative embodiments and need not be included in the same embodiment. Rather, some embodiments may use the fiber mesh 1912 (e.g., for simplicity and cost) and other embodiments may use the corner bend 1914 for both corners (e.g., to provide greater protection against mechanical damage caused by blunt force to the wall corners). One or more layers of stucco finish 1920 (cement- or acrylic-based) is applied over the exterior-facing fiber mesh reinforced cementitious (or other protective) layer 1916, patches of seam coat 1918, and first and second corner layers of seam coat 1918. A primer is typically not required when using acrylic-based stucco, although one can be used if desired.

FIGS. 19C and 19D show different perspective views of a model of another example stucco system 1900 for use in making an exterior wall of a complete wall structure according to the disclosure. The main difference between this embodiment and that of FIGS. 19A and 19B is that the embodiment in FIGS. 19C and 19D utilizes screws 1910 pared with enlarged washers 1912 to fasten a pair of adjacent first and second lightweight composite panels 1908a, 1908b to the wall frame 1902, which is formed using wooden studs 1904 and OSB sheathing 1906. A vertical concourse of screws 1910 and enlarged washers 1912 are used to interconnect the adjacent first and second lightweight composite panels 1908a, 1908b fastened to the OSB sheathing 1906. A vertical strip of fiber mesh tape 1916 is placed over the vertical concourse of screws 1910 and enlarged washers 1912 and a portion of exterior-facing fiber reinforced (or other protective) layers of the adjacent first and second lightweight composite panels 1908a, 1908b, followed by applying a vertical strip of an appropriate seam coat 1918 (e.g., thin set mortar or fine-sanded stucco) over the fiber mesh tape 1916, screws 1910, enlarged washers 1912, and a portion of the exterior-facing fiber reinforced (or other protective) layers to further tie the adjacent first and second lightweight composite panels 1908a, 1908b together. This further helps prevent separation and potential formation of cracks in a stucco finish 1920 applied over the joint between the adjacent first and second lightweight composite panels 1908a, 1908b. The vertical strip of seam coat 1916 also forms a more uniform surface to which the stucco finish 1920 can be applied.

The example stucco system 1900 also includes third and fourth lightweight composite panels 1908c, 1908d fastened to the wall frame 1902 and positioned at 90° angles relative to the first and second lightweight composite panels 1908a, 1908b to form first and second corners. The first corner is protected by fiber mesh 1916 and a first corner layer of seam coat 1918 (e.g., thin set mortar or fine-sanded stucco) in which the fiber mesh 1916 is embedded. The second corner is protected by a rigid metal corner bend 1914, which can be made of galvanized steel, and a second corner layer of seam coat 1918 covering the metal corner bend 1914. It will be understood that the fiber mesh 1916 and metal corner bend 1914 are alternative embodiments and need not be included in the same embodiment. Rather, some embodiments may use the fiber mesh 1916 (e.g., for simplicity and cost) and other embodiments may use the metal corner bend 1914 (e.g., to provide greater protection against mechanical damage caused by blunt force to wall corners). One or more layers of stucco finish 1920 (cement- or acrylic-based) is applied over the exterior-facing fiber mesh reinforced cementitious (or other protective) layers of the lightweight composite panels 1908 and patches of seam coat 1918.

FIGS. 20A and 20B are schematic diagrams that illustrate complete wall structures 2000 that include interior and exterior lightweight composite panels fastened to an underlying wall frame. FIG. 20A illustrates a complete wall structure 2000 that includes insulation 2005 within a cavity of a wall frame (not shown), first lightweight composite panels 2001 fastened to an interior side of the wall frame to form an interior wall, sheathing 2030 (e.g., OSB or lightweight composite panels) fastened to an exterior side of the wall frame, second lightweight composite panels 2002 fastened to the sheathing 2030, and a stucco finish 2022 applied to the second lightweight composite panels 2002.

FIG. 20B illustrates a complete wall structure 2000 that includes insulation 2005 within a cavity of a wall frame (not shown), first lightweight composite panels 2001 fastened to an interior side of the wall frame to form an interior wall, second lightweight composite panels 2002a fastened to an exterior side of the wall frame as wall sheathing (e.g., to replace OSB sheathing), a drainage layer 2003 attached over the second lightweight composite panels 2002a, third lightweight composite panels 2002b fastened to the second lightweight composite panel sheathing 2002a, and a stucco finish 2022 applied to the third lightweight composite panels 2002b.

FIG. 20C is a diagram that illustrates an exterior wall 2000 that includes lightweight composite panels 2002a, 2002b, 2002c, 2002d fastened by means of screw and enlarged washer ensembles 2004 to a wall frame (not shown) comprising studs and optionally sheathing (e.g., OSB or lightweight composite panels) to form an outer wall of a complete wall structure. The lightweight composite panels 2002a, 2002b, 2002c, 2002d form a substrate to which an exterior finish can be directly applied, such as stucco, brick veneers, stone, masonry, tiles, and other exterior finishes known in the art. In some embodiments, the lightweight composite panels 2002a, 2002b, 2002c, 2002d can replace OSB panels as exterior sheathing to form a complete wall structure. In such cases, the lightweight composite panels 2002a, 2002b, 2002c, 2002d can function as the shear wall. Seams or joints between adjacent lightweight composite panels 2002a, 2002b, 2002c, 2002d and other structural elements of the exterior wall 2000 may need to be sealed, such as by using polymer sealing tape 246 as illustrated in FIG. 2B.

FIG. 20C further shows a corner bend 2006 and fiber mesh tape 2008 applied over the corner formed by adjacent lightweight composite panels 2002a, 2002b, 2002c, 2002d placed at a right angle. A layer of seam coat (not shown) is thereafter applied over the corner bend 2006 and fiber mesh tape 2008 to form a reinforced corner 2010. A horizontal strip of fiber mesh tape (not shown) is placed over the horizontal seams or joints between adjacent vertically stacked lightweight composite panels 2002a, 2002b and 2002c, 2002d. A horizontal strip of seam coat 2012 is placed over the horizontal strip of fiber mesh tape (not shown) to tie the adjacent vertically stacked lightweight composite panels 2002a, 2002b together. This helps prevent separation and potential formation of cracks in a stucco finish applied over the joint between the vertically stacked lightweight composite panels 2002a, 2002b. Finally, a desired exterior finish is applied and adhered to the exterior wall 2000, including over the exterior surfaces of lightweight composite panels 2002a, 2002b, 2002c, 2002d and any seam coat 2012 or other underlying layers applied to the lightweight composite panels 2002a, 2002b, 2002c, 2002d.

FIG. 21A is a diagram that illustrates an exterior wall 2100 that includes lightweight composite panels 2112 fastened to an exterior side of a wall frame (not shown) using screws and enlarged washer ensembles 2116 to sheathing (not shown), which is covered by a layer of black paper 2108 and polymer wrap 2110. A layer of an appropriate seam coat 2118 (e.g., thin set mortar or fine-sanded stucco) is shown having been applied over a portion of the lightweight composite panels 2112 to cover enlarged washer ensembles (not shown) positioned beneath the layer of seam coat 2118. A first stucco layer 2120 is shown having been applied over a portion of the seam coat 2118. A stucco finish 2122 is shown having been applied over the first stucco layer 2120. In this case, the first stucco layer 2120 may be functionally similar to the brown coat of a traditional stucco system, but without having to first apply lath and a scratch coat. The first stucco layer 2120 may form a more uniform surface over which the stucco finish 2122 is applied and/or may enhance the bond of the stucco finish 2122 to the lightweight composite panels 2112 and/or may increase the strength and durability of the stucco system.

FIG. 21B is a diagram that illustrates an exterior wall 2100 that includes lightweight composite panels 2140 fastened to an exterior side of a wall frame (not shown), which is covered by a polymer wrap 2150, and illustrates various exterior finishes applied to the lightweight composite panels 2140. These include a stucco finish 2152, brick veneers 2154, and tiles 2156 applied over different portions of the lightweight composite panels 2140. A layer of fiber mesh 2158 and a layer of an appropriate bonding layer 2160 (e.g., thin set mortar or fine-sanded stucco) covering the fiber mesh 118 are applied over a portion of the lightweight composite panels 1140 to which the various finished are applied. The stucco finish 2152 (cement- or acrylic-based) can be applied directly over the bonding layer 2160. The brick veneers 2154 can be adhered to the bonding layer 2160 using thin set mortar (not clearly shown) and/or an adhesive. The tiles 2156 can be adhered to the bonding layer 2160 using thin set mortar (not shown) and/or an adhesive.

FIG. 22 illustrates the use of mesh tape 2202 as a template for proper placement of screws or other mechanical fasteners (not shown) when fastening a lightweight composite panel 2200 to studs 2110 or other structural elements of a wall frame (not shown). Placement of screws or other mechanical fasteners through the mesh tape 2202, preferably at or near the center line of the mesh tape 2202, helps ensure that the screws or other mechanical fasteners reliably engage the studs 2110 or other structural elements rather than being driven uselessly outside the studs or other structural elements.

In some embodiments, the screws or other fasteners used to attach lightweight composite panels to a wall frame include corresponding washers or enlarged heads that are at least about 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, or 80 mm, in diameter. This ensures sufficiently large surface contact between the screws or other fasteners and the fiber mesh reinforced cementitious (or other protective) layer so that the screws or other fasteners have a much lower tendency to tear through the lightweight composite panels or otherwise compromise the structural integrity of the wall structure formed by the lightweight composite panels.

To illustrate this point, FIG. 23 is a diagram that illustrates a lightweight composite panel 2300 with holes formed by screws 2310 passing all the way through the exterior fiber mesh reinforced cementitious layer. Remnants of fiber mesh 2320 of the damaged fiber mesh reinforced cementitious layer can be seen. The holes were the result of screw heads being too small (i.e., having too little surface area) to prevent the screw heads from perforating and penetrating all the way through the exterior fiber mesh reinforced cementitious layer. FIG. 23 further illustrates a screw 2310 with a washer 2330 abutting the surface of the lightweight composite panel 2300 without having passed through the exterior fiber mesh reinforced cementitious layer. Some cracking 2340 of the fiber mesh reinforced cementitious layer may occur, indicating that the washer 2330 may reduce, but not completely prevent, damage to the fiber mesh reinforced cementitious layer.

Reference is made to FIGS. 24A-24D, which illustrate the use of specialized washers with enlarged surface areas and penetrating prongs that help fix the washers in place relative to the lightweight composite panels, prevent rotation when screws are being driven into studs or other structural elements of a wall frame, and add additional lateral strength between the washers and the lightweight composite panels. The penetrating prongs can also be designed to abut the underlying stud or other structural element and act as a stop to prevent the washers and screws from being driven too far into the lightweight composite panel and undesirably crushing or fracturing the exterior fiber mesh reinforced cementitious (or other protective) layer, which could greatly reduce the shear strength of the exterior wall structure or roofing deck.

FIG. 24A more particularly illustrates the use of screws 2405 and specialized washers 2410 having a plurality of penetrating prongs 2420. The specialized washers 2410 can be rectangular in shape in order to overlap the end surfaces of adjacent lightweight composite panels 2400a, 2400b. The penetrating prongs 2420 penetrate through and become embedded within the lightweight composite panels 2400a, 2400b, including though the exterior fiber mesh reinforced cementitious (or other protective) layers and at least partially through the foam cores of the lightweight composite panels 2400a, 2400b. The penetrating prongs 2420 fix the specialized washers 2410 in a desired position relative to the lightweight composite panels 2400a, 2400b and prevent rotation while the screws 2405 are being driven through the lightweight composite panels 2400a, 2400b and into the underlying stud 2425 or other structural elements of a wall frame. The penetrating prongs 2420 thereby ensure that left and right wings of the specialized washers 2410 reliably overlap corresponding surfaces of adjacent lightweight composite panels 2400a, 2400b to tie them together. The penetrating prongs 2420 can also provide a load spreading/pressure spreading effect, i.e., the prongs 2420 can distribute normal and lateral pressure from the screw 2405 to the prongs. The specialized washers 2410 and penetrating prongs 2420 provide greater lateral tension of the screw and washer ensemble relative to the lightweight composite panels 2400a, 2400b, thereby increasing the overall shear strength of the wall structure. FIG. 24A also illustrates an embodiment of another specialized washer 2430 that has a circular shape.

FIGS. 24B-24D illustrate a fastener assembly 2400 comprising a screw 2402 and specialized washer 2404 with a circular shape, enlarged surface area, and penetrating prongs 2410 for attaching a lightweight composite panel 2420 to a stud 2450 or other structural element (e.g., OSB sheathing) of a wall frame. The penetrating prongs 2410 help fix the washer 2304 in place relative to the lightweight composite panel 2420 and prevent rotation of the washer 2404 when the screw 1402 is being driven into the stud 2450 or other structural element of a wall frame and add additional lateral strength between the washers 2404 and the lightweight composite building panel 2420. The penetrating prongs 2410 can also be designed to abut the underlying stud 2450 or other structural element and act as a stop to prevent the washer 2404 from being driven too far into the lightweight composite panel 2420 and undesirably crushing or fracturing the exterior fiber mesh reinforced cementitious (or other protective) layer 2422, which could reduce the shear or other strength of the wall structure.

FIG. 24B more particularly illustrates the use of a specialized fastener assembly 2400 comprising a screw 2402 and specialized washer 2404 having a body 2406 of enlarged diameter, a concave interior portion 2408, and a plurality of penetrating prongs 2410 extending laterally from the washer body 2406. Although the specialized washer 2404 in this embodiment is illustrated as having a circular washer body 2406, other embodiments of specialized washers may include enlarged rectangular-shaped washer bodies (not shown) designed to more completely overlap and adjoin adjacent lightweight composite panels during installation.

The penetrating prongs 2410 are designed to penetrate through and become embedded within a lightweight composite panel 2420, including though the exterior fiber mesh reinforced cementitious (or other protective) layer 2422, at least partially through the foam core 2424, and optionally through the interior fiber mesh reinforced cementitious (or other protective) layer 2426 and optional drainage layer (not shown) to make abutment with a stud 2450 or other structural element of a wall frame. The penetrating prongs 2410 help retain the specialized washer 2404 in a desired position relative to the lightweight composite panel 2420 and prevent rotation while the screw 2402 is being driven through the lightweight composite panel 2420 and into the underlying stud 2450 or other structural element of a wall frame. The penetrating prongs 2410 can also provide a load spreading/pressure spreading effect to distribute normal and lateral pressure from the screw 2402 and washer body 2406 to the prongs 2410. The specialized washer 2404 and penetrating prongs 2410 provide greater lateral tension of the screw and washer assembly 2400 relative to the lightweight composite building panel 2420, thereby increasing the overall strength, including shear strength, of the wall structure.

FIG. 24C is a bottom perspective view and FIG. 24D is a top perspective view that more particularly illustrate features of the specialized washer 2404. The washer body 2406 can have an enlarged diameter in order to provide higher surface area and increase contact between the specialized washer 2404 and an adjacent fiber reinforced cementitious (or other protective) layer of a lightweight composite panel 2420. The washer body 2406 can have a concave interior portion 2408, which permits an outer rim 2412 to become substantially flush with, and the concave interior portion 2408 to advance below, the adjacent fiber reinforced cementitious (or other protective) layer when used to attach a lightweight composite building panel 2420 to a wall frame, as shown in FIG. 24B. This allows the concave interior portion 2408 to partially compress the interior foam core 2424 and exterior fiber reinforced cementitious (or other protective) layer 2422 of the lightweight composite panel 2420 to provide firm and reliable attachment of the panel 2420 to the wall frame. The washer body 2406 can include a countersink 2414 that accommodates the head 2403 of the screw 2402 so that the screw head 2403 does not protrude beyond the surface of the washer body 2406 when driven into a stud 2450 or other structural element of a wall frame.

The length of the penetrating prongs 2410 can be selected to determine and limit how far the concave interior portion 2408 of the washer body 2406 is able to advance into and compress the lightweight composite panel 2420, forming a depression therein. The penetrating prongs 2410 can advantageously have a length in order to penetrate all the way through the lightweight composite panel 2420 and make contact with the stud 2450 or other structural element. In this way the penetrating prongs 2410 can act as a stop that limits how far the specialized washer 2404 can be driven toward and into the lightweight composite panel 2420. Providing a stop prevents the specialized washer 2404 from being driven too far into the lightweight composite panel 2420, thereby preserving the structural integrity and strength of the exterior fiber mesh reinforced cementitious (or other protective) layer 2422 adjacent to the specialized washer 2404. This preserves and maximizes the overall strength, including shear strength, of the wall structure.

In some embodiments, it may be desirable for the length of the penetrating prongs 2410 to be slightly less than the cross-sectional thickness of the lightweight composite panel 2420 in order to superficially compress, but not damage, the exterior fiber mesh reinforced cementitious (or other protective) layer 2422 toward the foam core 2424 to thereby increase the compressive force of the washer 2404 bearing against the lightweight composite panel 2420. This can increase the overall fixation strength of the fastening assembly 2400.

In the case where studs or other structural elements are wood so as to permit some degree of penetration by the penetrating prongs 2410, the length of the penetrating prongs 2410 can equal or slightly exceed the cross-sectional thickness of the lightweight composite panel 2400. In such case, the penetrating prongs 2410 can be allowed to penetrate and bite slightly into the wooden studs or other structural elements while still acting as a stop that prevents excessive penetration into the lightweight composite panels 2400 and avoiding damage to the exterior fiber mesh reinforced cementitious (or other protective) layer 2405. Penetration of the penetrating prongs 2410 into wooden studs or other structural elements of a wall frame can provide additional lateral fixation between the lightweight composite panels 2400 and the wall frame. This can further help tie adjacent lightweight composite panels 2400 together and increase the shear strength of the wall structure.

In some embodiments, sealing one or more joints or seams between adjacent lightweight composite panels includes applying waterproof tape, metal flashing, polyurethane foam, fiber mesh tape and an appropriate seam coat (e.g., thin set mortar or fine sanded stucco), or other sealing means known in the over the joints or seams, including joints or seams in the wall face and corners. In addition, joints, seams, openings, or gaps between lightweight composite panels and other structural elements, such as wooden or metal beams or posts, vent pipes in roofs, fixtures, and the like, can be filled using sealing means known in the art, such as polyurethane foam, metal flashing, or tar.

In some embodiments, an appropriate seam coat can be applied over at least a portion of the exterior facing fiber mesh reinforced cementitious (or other protective) layer, including over any exposed screws, washers, or other mechanical fasteners used to attach the lightweight composite panels to the exterior wall structure, and over any joints or seams, fiber mesh tape, polyurethane, or other exposed sealants on or in the exterior wall structure.

Additional Terms & Definitions

While certain embodiments of the present disclosure have been described in detail, with reference to specific configurations, parameters, components, elements, etcetera, the descriptions are illustrative and are not to be construed as limiting the scope of the claimed invention.

Furthermore, it should be understood that for any given element of component of a described embodiment, any of the possible alternatives listed for that element or component may generally be used individually or in combination with one another, unless implicitly or explicitly stated otherwise.

In addition, unless otherwise indicated, numbers expressing quantities, constituents, distances, or other measurements used in the specification and claims are to be understood as optionally being modified by the term “about” or its synonyms. When the terms “about,” “approximately,” “substantially,” or the like are used in conjunction with a stated amount, value, or condition, it may be taken to mean an amount, value or condition that deviates by less than 20%, less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01% of the stated amount, value, or condition. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Any headings and subheadings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims.

It will also be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” do not exclude plural referents unless the context clearly dictates otherwise. Thus, for example, an embodiment referencing a singular referent (e.g., “widget”) may also include two or more such referents.

It will also be appreciated that embodiments described herein may also include properties and/or features (e.g., ingredients, components, members, elements, parts, and/or portions) described in one or more separate embodiments and are not necessarily limited strictly to the features expressly described for that particular embodiment. Accordingly, the various features of a given embodiment can be combined with and/or incorporated into other embodiments of the present disclosure. Thus, disclosure of certain features relative to a specific embodiment of the present disclosure should not be construed as limiting application or inclusion of said features to the specific embodiment. Rather, it will be appreciated that other embodiments can also include such features.