Lightweight composite panels and compositions and methods for manufacturing and using same

Abstract

Lightweight composite panels, compositions used to make composite panels, and methods for manufacturing composite panels. The composite panels include a lightweight foam core sandwiched between thin protective layers (e.g., fiber reinforced cementitious layer, thermoset polymer layer, e.g., polyurea or polyaspartic, or magnesium oxide). Lightweight composite panels can be used in place of conventional wallboards and panels, including for various uses such as interior drywall, backerboard for tile and other interior finishes, including those exposed to moisture, exterior sheathing, floor underlayment, soffits, roofing decks, shaft liners, and the like. Lightweight composite panels can be cut, drilled, and screwed onto structural elements of buildings, such as wall frames comprising wooden or metal studs, roof frames comprising boards, studs, or trusses, floor joists, concrete floors, foundations, and the like. Exterior sheathing panels can include a drainage layer and / or a factory installed finish. Interior panels that replace gypsum boards can include a plaster layer.

Description

LIGHTWEIGHT COMPOSITE PANELS AND COMPOSITIONSAND METHODS FOR MANUFACTURING AND USING SAMEBACKGROUNDTechnical Field

[0001] This disclosure relates to lightweight composite panels and compositions and methods for making and using lightweight composite panels and variations thereof.Related Technology

[0002] 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.

[0003] 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.

[0004] While suitable for walls which are not exposed to water, drywall is not suitable for applications exposed to water and high humidity environments. Drywall 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, dry wall will likely need to be removed and replaced. Furthermore, the paper facings and organic- Page 1 - Docket No. 23807.1aadditives mixed with the gypsum can be a breeding ground for mold.

[0005] Another issue is fire and thermal resistance. While gypsum drywall can provide a level of fire and heat resistance, multiple layers or thick assemblies are often required, increasing weight, material use, cost and labor. Gypsum-based panels are highly susceptible to water damage, mold growth, and structural degradation in high-humidity environments or areas prone to water leaks.

[0006] Another issue with gypsum board is the outer surface is paper, which appears unfinished and requires application thereto of one more finishing layers, such as paint and / or wallpaper. While paint and wallpaper can readily adhere to the paper surface of gypsum board, some builders and homeowners will apply a thin plaster coating layer (e.g., skim coat) over the paper layer to reinforce the drywall and provide a more even and durable surface to which a finish can be applied.

[0007] Another issue with traditional gypsum 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.

[0008] For applications where walls will be exposed to moisture, such as in bathrooms, particularly showers and bathtubs, cement board is typically used. Cement board is a combination of cement and reinforcing fibers formed into sheets of varying thickness. They are 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.

[0009] As tile backer board, cement board has better long-term performance than paperfaced 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. Cement board is typically made to breath and is not waterproof per se. It can absorb- Page 2 - Docket No. 23807.1amoisture 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 boards or a trowel-applied waterproofing product (e.g., liquid membrane) can be applied to the face of the boards behind the finish system.

[0010] 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 of 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.

[0011] 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.

[0012] 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 compromise 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 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.

[0013] Examples of finishes that can be applied over exterior wall and roof sheathing- Page 3 - Docket No. 23807.1ainclude, but are not limited to, stucco, thin bricks, natural and manufactured stone veneers, tiles, shingles, metal cladding, and the like. In addition to applying an appropriate water- resistive barrier (WRB), application of finishes typically requires means for attaching them to sheathing or other structural elements of a wall or roof structure.

[0014] Stucco is a common finish applied to exterior walls of houses, apartments, town houses, condominium, 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 (e.g., when standing on scaffolding).

[0015] In a traditional stucco system applied to a building with exterior sheathing comprising wooden boards (e.g., OSB panels), the sheathing is wrapped with one or more layers (e.g., polymer membrane and / or a black paper layer) to provide protection against moisture. Next, lath, which is typically some type of wire mesh, is installed over the one or more outer protective layers, typically using staples and / or nails. A scratch coat made from sand, cement, water, and optional components is applied over the lath using a trowel or sprayer, followed by forming rough horizontal ridges and troughs using a scarifier tool while the scratch coat is still in a plastic state. A brown coat made from sand, cement, water, and optional components is applied over the scratch coat to provide a smooth surface to which the stucco finish is applied. The scratch coat provides both mechanical and chemical bonding of the brown coat. Finally, a stucco finish is applied over the brown coat. Cementbased stucco is typically applied directly to the brown coat. If acrylic stucco is the final finish, a primer can be applied to the brown coat to improve adhesion and prevent delamination of the acrylic stucco finish.

[0016] In an EIFS stucco system, a building with exterior sheathing comprising wooden boards (e.g., OSB panels) is coated with a liquid moisture barrier material, which hardens into a solid moisture barrier layer. A primer is applied over the moisture barrier layer, and a rain screen, e.g., an adhesive layer with spaced apart notches or ridges that act vertical drainage channels is applied to the primer. An insulating foam layer is placed over the adhesive layer, which bonds the foam layer to the wall. A base coat with embedded mesh is applied over the foam layer. The base coat can comprise thin set mortar, optionally with a primer (or a primer can be applied over the base coat). In some cases, as second base coat may be applied to fully embed and hide the mesh. Finally, a stucco finish is applied over the base coat. The stucco finish is typically acrylic stucco, which is why a primer may be- Page 4 - Docket No. 23807.1arequired on or in the base coat. Alternatively, the stucco finish can be cement stucco

[0017] Accordingly, there remains a need for improved building panels for interior and exterior use, including improved wall panels that can substitute for drywall panels, as well as structural panels for exterior use, such as sheathing and underlayments for wall and roofing structures, wherein the building panels are waterproof, provide high strength, are lightweight to facilitate installation, and are resistant to heat and combustion, and can provide a substrate for attachment of desired finishes.SUMMARY

[0018] Disclosed are lightweight composite panels, compositions for making lightweight composite panels and variations thereof, and methods of manufacturing and using lightweight composite panels and variations thereof. The lightweight composite panels can be used in place of conventional wallboards and panels, including for a variety of uses, such as interior panels that can substitute for gypsum wallboard, backer boards for tile and other interior finishes, including those exposed to moisture, exterior wall sheathing or cladding, and substrates for application of finishes, floor underlayment, soffits, roofing decks and roof elements applied thereto, shaft liners, and the like.

[0019] Also disclosed are “lightweight composite building panels” with incorporated drainage layer that facilitates moisture removal and methods of manufacturing and using lightweight composite building panels with incorporated drainage layer. The lightweight composite building panels with incorporated drainage layer can be used in place of conventional building panels, including but not limited to exterior wall sheathing, underlayments, backer boards, soffits, roofing decks, and the like.

[0020] Also disclosed are “lightweight composite plaster panels” and compositions and methods for manufacturing lightweight composite plaster panels. The lightweight composite plaster panels can be used in place of gypsum wallboard for making interior walls and ceilings and are advantageously strong, lightweight, and moisture and heat resistant. The lightweight composite plaster panels can have a plaster show layer (i.e., that faces outwardly) having a desired surface finish, such as smooth or textured.

[0021] The lightweight composite panels comprise a lightweight foam core sandwiched between first and second protective layers selected from a fiber mesh reinforced cementitious composition, cured thermoset resin, or other rigid material. The lightweight composite panels can be cut, drilled, and screwed onto structural elements of buildings, such as wall frames comprising wooden or metal studs, roof frames comprising boards, studs, or trusses, floor joists, concrete floors, foundations, and the like.- Page 5 - Docket No. 23807.1a

[0022] In some embodiments, the lightweight composite panels can be modified by applying a drainage layer (e.g., on an interior composite panel surface) to yield lightweight composite building panels with incorporated drainage layer that facilitates moisture removal. In other embodiments, the lightweight composite panels can be modified by applying a plaster layer (e.g., on an exterior composite panel surface) to yield a lightweight composite plaster panel with a plaster show layer (i.e., that faces outwardly) having a desired surface finish, such as smooth or textured. Is either case, the lightweight composite panel can be referred to as a “core composite panel structure” to which the drainage layer or plaster layer are applied.

[0023] In some embodiments, one or more protective layers of the lightweight composite panels (core composite panels) may comprise a fiber mesh reinforced cementitious composition. As a result, the lightweight composite panels (core composite panels) are strong and can support relatively heavy loads using nails, screws, and other fasteners known in the art. Protective layers made from fiber mesh reinforced cementitious composition can be “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, in cross-sectional thickness), are 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 filament mesh but can be made of other strong fibers or filaments, such as carbon fibers or filaments.

[0024] In addition to, or instead of, a fiber mesh reinforced cementitious layer, one or both protective layers of the lightweight composite panels (core composite panels) may comprise other materials in addition to or instead of the fiber mesh reinforced 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, woven, 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.

[0025] The lightweight foam core is typically made from extruded polystyrene foam (XPS) but can alternately comprise expanded polystyrene foam (EPS), polyisocyanurate- Page 6 - Docket No. 23807.1afoam, polyurethane (PUR) foam, phenolic polymers (e.g., phenol-formaldehyde) melamine polymers (e.g., melamine-formaldehyde), and / or other thermoplastic and thermoset polymers known in the art that can be formed into rigid or semi-rigid foam layers. Alternatively, the foam core may comprise an inorganic foam materials, such as a refractory foam material, to provide additional fire-resistance. Examples include silica gel, aerogel, silicate foams, urea-silicate foam, SiOC / SiC, ceramic foams, refractory foams, and the like. The inorganic foam core can resist melting even when exposed to fire or intense heat in order for the core composite panel structure to maintain its structural integrity.

[0026] In some embodiments, lightweight composite panels (core composite panels) are manufactured by applying a fiber (e.g., fiberglass) mesh and cementitious or curable resin composition onto front and back surfaces of a foam sheet, such as an XPS or other polymer 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.

[0027] In some embodiments, the panels can include a pre-applied surface finish, such as stucco, thin bricks, natural and manufactured stone veneers, tiles, roofing shingles, wood shakes, metal cladding, and the like, on an exterior surface facing away from a wall or roof frame (e.g., adhered to the exterior fiber mesh reinforced cementitious layer). In such cases, the lightweight composite panels may also include a drainage layer to facilitate removal of moisture between the lightweight composite panels and the underlying wall or roof structure.

[0028] In some embodiments, the lightweight composite panels can be modified to function as lightweight composite building panels, such as when constructing exterior wall structures, that facilitate removal of moisture between the panels and underlying building structure. The lightweight composite panel (core composite panel structure) can be modified by attaching a drainage layer (e.g., polymer uncoupling membrane, embossment, drainage- Page 7 - Docket No. 23807.1aplane, rain screen, dimple board, factory applied dimples or dots, or bleed layer (collectively “drainage layer”) to an interior surface that is designed to face a wall or roof structure. 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

[0029] 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.

[0030] In some embodiments, the lightweight composite building panels have an exterior surface that facilitates direct attachment of a desired surface finish, such as stucco, thin bricks, natural and manufactured stone veneers, tiles, roofing shingles, wood shakes, metal cladding, and the like. For example, a desired finish can be adhered to an exterior fiber mesh reinforced cementitious layer. The lightweight composite building panels include the aforementioned drainage layer to facilitate removal of moisture between the lightweight composite building panels and the underlying wall or roof structure.

[0031] In some embodiments, the lightweight composite panels can be modified to be lightweight composite plaster panels, which can be used to form interior wall structures. In some embodiments, the outer / exposed surface of the core composite panel structure and optionally the side edges can be covered by the plaster layer. The interior surface of the lightweight composite plaster panel (i.e., that faces inwardly) can omit a plaster layer and have a textured surface that facilitates the use of glue or other adhesives to attach lightweight composite plaster panels to structural elements of a building, such as interior wall studs or ceiling joists.- Page 8 - Docket No. 23807.1a

[0032] The lightweight composite plaster panels can be cut, drilled, screwed, or glued onto structural elements of buildings, such as interior wall studs or ceiling joists. The lightweight composite plaster panels are advantageously lightweight yet strong and able to support relatively heavy loads, such as pictures or other items attached using nails or other hangers or wall-mounted televisions attached using screws or other wall attachment systems. The composite plaster panels can be moisture-resistant (e.g., waterproof) and heat- resistant (e.g., fire resistant), and have high structural strength (e.g., high tensile strength, flexural strength, and / or toughness).

[0033] Because the core composite panel structure comprises a strong lightweight foam core sandwiched between two fiber mesh reinforced cementitious (or other rigid protective) layers, and because the plaster layer applied to the core composite panel structure can be thin and lightweight, the lightweight composite plaster panels disclosed herein are both lighter weight and stronger than conventional gypsum wallboard. Moreover, the core composite panel structure and plaster layer can be waterproof, providing extra safety if the lightweight composite plaster panels are inadvertently exposed to moisture. The plaster layer is typically made from a cementitious plaster composition comprised of hydraulic cement, calcium carbonate, water, and other components, which can harden and cure to become strong and water-resistant. In some embodiments, the lightweight composite plaster panels can include beveled edges (e.g., 2 or 4) to permit placement of multiple adjacent lightweight composite plaster panels to a wall to form beveled joints, followed by the application of drywall patch (taping and mudding) to hide the beveled joints.

[0034] In some embodiments, the fiber mesh reinforced cementitious (or other rigid protective) layer of the core composite panel structure can have a grid pattern or other texture or discontinuities that may be desirably smoothed out by the plaster layer in order to yield composite plaster panels having a smooth surface, at least on the show side that is intended to receive a subsequent finish, such as paint or wallpaper. Alternatively, the plaster layer can have a textured surface or other non-smooth finish to provide a desired look or functionality (e.g., old world or traditional lath and plaster look).

[0035] The lightweight composite panels, including lightweight composite building panels and lightweight composite plaster panels, can be fastened to interior walls, exterior walls or roof structures of a building using mechanical fasteners and adhesives known in the art, such as wood screws, sheet metal screws, nails, rivets, and construction adhesive. Mechanical fasteners 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- Page 9 - Docket No. 23807.1alightweight composite panels to studs or other structural elements of wall or roof structures. To prevent screws from tearing through the exterior fiber mesh reinforced cementitious layer, screws can be used with enlarged washers having high surface area to distribute the pressure or load over a high surface area of the lightweight composite panels. Specialized washers with penetrating prongs can be used (e.g., with screws) to limit rotation and penetration, preventing damage to the lightweight composite building panels. Rectangular washers with multiple prongs on either side of the screw can be used to tie adjacent lightweight composite panels together. The penetrating prongs can have a length so that the washers lie flush with or just below the surface of the exterior fiber mesh reinforced cementitious layer. A patch coating can be applied over the washers to fill any indentations caused by the washers or other mechanical fasteners.

[0036] 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 claimedBRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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:

[0038] Figure 1 A is a side perspective view that illustrates examples of differently-sized lightweight composite panels and core composite panel structures;

[0039] Figure IB is a top perspective view that illustrates the differently sized lightweight composite panels and core composite panel structures of Figure 1A;

[0040] Figure 2 is an exploded diagram that schematically illustrates the layered structure of the lightweight composite panels and core composite panel structures of Figures 1 A and IB;

[0041] Figure 3 is a detailed flow chart that illustrates an example method of manufacturing lightweight composite panels and core composite panel structures;

[0042] Figures 4A-4C illustrate an embodiment of a specialized fastener assembly comprising a screw and specialized washer with multiple prongs designed to penetrate at- Page 10 - Docket No. 23807.1aleast partially through and become embedded within the lightweight composite panels, lightweight composite building panels, and lightweight composite plaster panels;

[0043] Figures 5 A and 5B illustrate examples of lightweight composite building 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;

[0044] Figures 6A-6D illustrate alternative embodiments of drainage layers, variously known as uncoupling membranes, drainage planes, rain screens, dimple boards, or bleed layers, with gaps or channels that can be attached incorporated with core composite panel structures to facilitate removal of moisture from between the lightweight composite building panels and an exterior wall or roof structure to which they are attached;

[0045] Figures 7A-7C 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;

[0046] Figure 8 illustrates a lightweight composite building panel with an applied stucco finish on the exterior fiber mesh reinforced cementitious layer;

[0047] Figure 9 illustrates lightweight composite building panels attached a wall frame with OSB sheathing using enlarged washers to form a wall with fiber mesh and corner bend applied over comers, a seam coat covering the fiber mesh and corner bend, and an applied stucco finish over the seam coat;

[0048] Figure 10 illustrates an exterior wall made using lightweight composite panels as sheathing with various applied exterior finishes, including stucco, stone, and tiles applied over exterior fiber mesh reinforced cementitious layers;

[0049] Figure 11 illustrates a lightweight composite panel with thin bricks applied to an exterior surface thereof for use as exterior sheathing or cladding with pre-applied finish;

[0050] Figure 12 is a perspective view that illustrates an example lightweight composite plaster panel, with the different layers being visible, including a textured finish layer;

[0051] Figures 13 A-13C illustrate an example lightweight composite plaster panel, with the different layers being visible, including a smooth finish layer;

[0052] Figure 14A is a perspective view that schematically illustrates an embodiment of a lightweight composite plaster panel with a bevel extending to each of the four edges;

[0053] Figure 14B is a cross-sectional view that schematically illustrates the layered structure of a lightweight composite plaster panel with beveled edges;- Page 11 - Docket No. 23807.1a

[0054] Figure 14C is an exploded diagram that schematically illustrates the layered structure of the lightweight composite plaster panel of Figure 14B;

[0055] Figure 15A is a cross-sectional view that schematically illustrates the layered structure of an embodiment of a lightweight composite plaster panel with beveled edges;

[0056] Figure 15B is an exploded diagram that schematically illustrates the layered structure of the lightweight composite plaster panel of Figure 15 A;

[0057] Figure 16A illustrates a pair of lightweight composite plaster panels abutting each other, with beveled edges forming a channel or depression that can be filled with tape and drywall patch during installation;

[0058] Figure 16B is a photograph showing a pair of lightweight composite plaster panels abutting each other, with the beveled edges covered by drywall patch or plaster; and

[0059] Figure 17 schematically illustrates an apparatus for grinding or trimming bevels in a core composite panel structure before applying the plaster layer.DETAILED DESCRIPTIONI. Overview

[0060] Disclosed herein are lightweight composite panels that are strong, lightweight, moisture resistant, and heat resistant. Also disclosed are compositions and methods for manufacturing lightweight composite panels and variations thereof. The lightweight composite panels comprise a lightweight polymer or inorganic foam core sandwiched between first and second protective layers of fiber mesh reinforced cementitious, thermoset polymer, and / or other rigid protective material. The lightweight foam core can be made of a polymer foam, such as closed cell polystyrene foam, to provide a water-resistant barrier that can, in some embodiments, can be 100% waterproof. The lightweight composite panels can be used, in basic or modified form, in place of conventional wallboards and panels, including for a variety of uses such as interior drywall, backer boards for tile and other interior finishes, including those exposed to moisture, exterior wall sheathing and cladding, substrates with finishes applied thereto, floor underlayment, soffits, roofing decks and roof elements applied thereto, shaft liners, and the like.

[0061] The lightweight composite panels can be cut, drilled, and fastened to structural elements of buildings, such as interior and exterior wall frames comprising wooden or metal studs, roof frames comprising boards, studs, or trusses, floor joists, concrete floors, foundations, and the like. Because both sides comprise a fiber mesh reinforced cementitious composition, the lightweight composite panels are strong and can be nailed or screwed into and support relatively heavy loads, such as thin bricks, wall tiles, stone, stucco, roofing tiles,- Page 12 - Docket No. 23807.1ashingles, metal cladding, wood shakes, and other finishes applied thereto and / or fixtures or other items using nails, screws, or other fasteners known in the art. A drainage layer can be applied to an interior surface of the lightweight composite panels to facilitate removal of moisture from between the lightweight composite panels and the underlying wall or roof structure. The lightweight composite panels can be fastened to wall or roof structures of a building using mechanical fasteners and adhesives known in the art, such as wood screws, sheet metal screws, nails, rivets, and construction adhesive. Specialized washers with penetrating prongs can be used (e.g., with screws) to limit rotation and penetration, preventing damage to the lightweight composite panels.

[0062] In some embodiments, the lightweight composite panels can be modified to be “lightweight composite building panels” by incorporating a drainage layer that facilitates removal of moisture between the building panels and sheathing or other structural elements to which they are attached. Also disclosed are compositions and methods for manufacturing lightweight composite building panels with incorporated drainage layer. The lightweight composite building panels can be used in place of conventional building panels including, but not limited to, exterior wall sheathing, underlayments, backer boards, soffits, roofing decks, and the like. The lightweight composite building panels can have an exterior surface that facilitates direct attachment thereto of a desired surface finish, such as stucco, thin bricks, natural and manufactured stone veneers, tiles, roofing shingles, wood shakes, metal cladding, and the like.

[0063] The lightweight composite building panels comprise a core composite panel structure (i.e., basic lightweight composite panel) and a drainage layer incorporated onto a side of the core composite panel. The core composite panel structure comprises a lightweight foam core sandwiched between first and second protective layers, such as a fiber mesh reinforced cementitious composition and / or cured thermoset resin or other rigid material. The drainage layer can be applied (e.g., attached, adhered, or fastened) to a side of the core composite panel structure that is intended to face an exterior wall or roof frame (e.g., to facilitate removal of moisture from between the lightweight composite building panels and the exterior wall or roof 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 preformed or molded to include gaps and channels that can function as a drainage layer to facilitate moisture removal

[0064] The lightweight composite building panels can be cut, drilled, and screwed,- Page 13 - Docket No. 23807.1anailed, or glued to structural elements of buildings, such as wall frames comprising wooden or metal studs, roof frames comprising boards, studs, or trusses, exterior sheathing (e.g., OSB panels), and the like. Specialized washers with penetrating prongs can be used (e.g., with screws) to limit rotation and penetration, preventing damage to the lightweight composite building panels.

[0065] In other embodiments, the lightweight composite panels can be modified to be “lightweight composite plaster panels” by applying a plaster layer for form a show surface, such as for use in making interior walls or ceilings. Also disclosed are compositions and methods for manufacturing lightweight composite plaster panels. The lightweight composite plaster panels include a core composite panel structure (i.e., basic lightweight composite panel) comprised of a lightweight foam core sandwiched between first and second protective layers, such as a fiber mesh reinforced cementitious composition and / or cured thermoset resin or other rigid protective material. A plaster layer is applied over one or both sides of the core composite panel structure to yield lightweight composite plaster panels. The plaster layer is typically applied as a flowable cementitious composition to at least one side of the core composite panel structure and caused or allowed to harden and cure. The lightweight composite plaster panels can be cut, drilled, and screwed, nailed, or glued onto structural elements of buildings, such as interior wall studs or ceiling joistsII. Lightweight Composite Panels (Core Composite Panel Structures)

[0066] Reference is made to Figures 1-3. Figures 1A and IB illustrate examples of lightweight composite panels (core composite panel structures) 100a, 100b, 100c of varying cross-sectional thickness that can be used as is or modified with other features for a specific purpose. Figures 1 A and IB show the layered structure of the lightweight composite panels (core composite panel structures) 100a, 100b, 100c, including strong, lightweight, and moisture-resistant extruded polystyrene (XPS) foam cores 110a, 110b, 110c sandwiched between first fiber mesh reinforced cementitious layers 120a, 120b, 120c and second fiber mesh reinforced cementitious layers 130a, 130b, 130c. 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.

[0067] The cross-sectional thickness of lightweight composite panels (core composite panel structures) 100a, 100b, 100c 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 Figures 1 A and IB, the cross-sectional thicknesses- Page 14 - Docket No. 23807.1aof the lightweight composite panels (core composite panel structures) 100a, 100b, 100c varies mostly or entirely depending on the cross-sectional thickness of the foam cores 110a, 110b, 110c. Although not shown, when lightweight composite panels (core composite panel structures) 100 of greater cross-sectional thickness are desired, it may be desirable to increase the thickness of the fiber mesh reinforced cementitious layers 120, 130 (e.g., to account for possible strength reduction caused by including a foam core 110 of greater cross sectional thickness).

[0068] Figure 2 is in an exploded view that schematically illustrates the layered structure of a lightweight composite panel (core composite panel structure) 200, which is similar or identical to the lightweight composite panels (core composite panel structures) 100a, 100b, 100c of Figures 1A and IB. The foam core 210 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 210 may have a density of about 30-45 kg / m3and a compressive strength of about 250-400 kPa.

[0069] Alternatively, the foam cores 110, 210 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., phenolformaldehyde) 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 semirigid 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.

[0070] 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- Page 15 - Docket No. 23807.1aTable 2Table 3- Page 16 - Docket No. 23807.1a

[0071] With reference to Figure 2, formed over first and second outer surfaces of the foam core 210 are first and second layers of fiber (e.g., fiberglass) mesh 220b, 230b, respectively, which become embedded within respective first and second layers of fresh cementitious composition applied over the fiber mesh layers 220b, 230b, which harden or cure to form first and second cementitious layers 220a, 230a. Together, the hardened cementitious layers 220a, 230a and embedded fiberglass mesh layers 220b, 230b form first and second fiber mesh reinforced cementitious layers 220, 230, which adhere to the foam core 210 to form a strong but lightweight composite panel structure. The fiber mesh layers 220b, 230b can alternatively include other fibers or filaments, such as carbon fibers or filaments.

[0072] 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).

[0073] Alternatively, the foam core may comprise an inorganic foam, such as a refractory foam material, to provide additional fire-resistance. Examples include silica gel, aerogel, silicate foams, urea-silicate foam, SiOC / SiC, ceramic foams, refractory foams, and the like. 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.

[0074] Figure 3 is a process flow chart that illustrates an embodiment of a method of manufacturing lightweight composite panels (core composite panel structures). In some embodiments, the lightweight composite panels (core composite panel structures) are manufactured by applying a fiber (e.g., fiberglass) mesh and fresh cementitious composition onto first and second surfaces of a rigid polymer (e.g., XPS) or inorganic foam core and- Page 17 - Docket No. 23807.1acausing or allowing the applied cementitious composition to harden. The fiber mesh becomes embedded in the hardened cementitious layer to enhance strength, increase toughness, and prevent cracking of the hardened cementitious layer. Alternatively, at least one of the hardened cementitious layers can be replaced or augmented with a cured polymer layer.

[0075] 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, about 1-2 mm, or about 1.25-1.75 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 x 4 mm with a strand diameter of about 0.5-1.0 mm.

[0076] As discussed in detail below in the section entitled “Lightweight Composite Plaster Panels”), where it is desired for lightweight composite plaster panels to have beveled edges (e.g., to accommodate mesh tape and wall patch to join adjacent composite plaster panels together), the fiber mesh reinforced cementitious layer of the core composite panel structure can be applied before or after forming beveled edges in the form core when forming the core composite structure. To maximize strength and performance, the fiber mesh reinforced cementitious (or other rigid) layer can be applied after forming beveled edges in the foam core to create a continuous fiber mesh reinforced cementitious (or other protective) layer across the entire surface of the core composite panel structure before applying a plaster layer.

[0077] In some embodiments, the fresh cementitious composition used to make one or more protective layers of the lightweight composite panels (core composite panel structures) 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,- Page 18 - Docket No. 23807.1aand / or expanded glass, which can increase fire and heat resistance.

[0078] 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)

[0079] The hydraulic cement typically i ncludes 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.

[0080] The components of the cementitious composition can be mixed by high-- Page 19 - Docket No. 23807.1aperformance 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.

[0081] 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 (core) 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.

[0082] In some embodiments, when manufacturing the lightweight (core) 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.- Page 20 - Docket No. 23807.1aIn 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 (core) 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.

[0083] In addition to, or instead of, a fiber mesh reinformed cementitious layer, one or both protective layers of the lightweight composite panel (core composite panel structure) 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.

[0084] 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, quasiprepolymer 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 predispersed 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.

[0085] The chemical structure of polyurea is as follows:- Page 21 - Docket No. 23807.1a

[0086] In a polyurea, alternating monomer units of isocyanates and amines react with each other to form urea linkages, as shown below.

[0087] 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:polyaspartic ester diisocyanatepolyaspartic

[0088] 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.

[0089] 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, thin bricks, 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- Page 22 - Docket No. 23807.1abrown 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).

[0090] Additional information and features relating to lightweight composite panels (core composite panel structures) and their uses in making various building products are disclosed in U.S. Prov. App. No. 63 / 686,489, filed Aug. 23, 2024; U.S. Prov. App. No. 63 / 692,563, filed Sep. 9, 2024; U.S. Prov. App. No. 63 / 703,834, filed Oct. 4, 2024; U.S. Prov. App. No. 63 / 720,649, filed Nov. 14, 2024; U.S. Prov. App. No. 63 / 729,637, filed Dec. 9, 2024; U.S. Prov. App. No. 63 / 744,115, filed Jan. 10, 2025; U.S. Prov. App. No. 63 / 747,543, filed Jan. 1, 2025; U.S. Prov. App. No. 63 / 753,600, filed Feb. 4, 2025; U.S. Prov. App. No. 63 / 764,354, filed Feb. 27, 2025; U.S. Prov. App. No. 63 / 788,276, filed Apr. 14, 2025; U.S. Prov. App. No. 63 / 849,709, filed Jul. 23, 2025, U.S. Prov. App. No. 63 / 855,715, filed Aug. 1, 2025, U.S. Prov. App. No. 63 / 857,807, filed Aug. 5, 2025, and U.S. Prov. App. No. 63 / 862,235, filed Aug. 12, 2025. The foregoing applications are incorporated by reference in their entirety.

[0091] 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, thin brick, 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. The lightweight composite panels can also be modified to include a plaster layer, forming lightweight composite plaster panels, can include beveled edges if desired.

[0092] The lightweight composite panels can include a polymer-modified cementitious coating layer, which facilitates adhesion of the cementitious layers to the foam core and also tiles or other surface finishes to an exposed composite panel surface. The fiberglass mesh embedded in the cementitious layers adds additional strength and rigidity to the overall- Page 23 - Docket No. 23807.1acomposite structure of the lightweight composite panels. For uses contemplating application of tile or other products on an exposed surface, the lightweight composite panels can have a textured surface that facilitates application of adhesive / glue / cement to hold tiles and other products to the composite panel surface.

[0093] Advantages of the lightweight composite panels include: being lightweight (i.e., approximately 1 / 3 the weight of gypsum drywall and approximately 1 / 6 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.

[0094] Other advantages include the following:

[0095] Benefits from being lighter weight than dry wall: a. delivery to site is cheaper; can ship 3 times more per truckload to the site; b. easier to carry panels around job site because 1 / 3 the weight; c. lower labor due to light weight; doesn’t require two people to carry and hang panels.

[0096] Benefit from being waterproof: a. no shrinkage from moisture on site (meaning if it rains on a pile of drywall awaiting use, they often have to throw away the top layer, or some of rest if water entered sides); b. no mold risk, and less likely to have to be tom out and replaced if there is a leak in the house.

[0097] Benefits from just not being dusty gypsum: a. Less likely to crack or break if dropped; b. no gypsum dust.

[0098] Benefits from insulation: a. four times higher R-value; b. Some sound reduction.

[0099] Stronger: a. less likely to be damaged during construction transportation and handling; b. advantages in roofing applications (discussed below); c. performs as a structural panel for prescriptive braced walls or shear walls.- Page 24 - Docket No. 23807.1a

[0100] Weather resistant: a. very low freeze and thaw deformation, rate of 0.014% (relevant to outdoor applications).III. Example Uses and Variations of Lightweight Composite Panels

[0101] The lightweight composite panels and variations thereof (e.g., lightweight composite building panels and lightweight composite plaster panels) can be used in place of conventional wallboards and panels, including for a variety of uses such as interior drywall, backer boards for tile and other interior finishes, including those exposed to moisture, exterior wall sheathing and finishes applied thereto, floor underlayment, soffits, roofing decks and roof elements applied thereto, shaft liners, and the like.

[0102] The lightweight composite panels and variations thereof can be cut, drilled, and fastened to structural elements of buildings, such as interior and exterior wall frames comprising wooden or metal studs, roof frames comprising boards, studs, or trusses, floor joists, concrete floors, foundations, and the like. Because both sides of the lightweight panels (or core composite panel structures) comprise a fiber mesh reinforced cementitious composition, the lightweight composite panels and variations thereof are strong and can be nailed or screwed into and support relatively heavy loads, such as thin bricks, wall tiles, stone, stucco, roofing tiles, shingles, metal cladding, wood shakes, and other finishes applied thereto and / or fixtures or other items using nails, screws, or other fasteners known in the art.

[0103] In some embodiments, lightweight composite panels, particularly lightweight composite building panels, can be used as backing for exterior finishes, such as stucco, thin bricks, stone, or other finishes. In such cases, the lightweight composite panels for exterior use, including for application of a surface finish, can include a drainage layer, such as an uncoupling membrane, drainage plane, rain screen, dimple board, or bleed layer, which provides gaps and channels between the lightweight composite panels and the underlying building surface to permit moisture (e.g., from ingress or condensation) to collect, drain and / or evaporate, thereby protecting the outer surface finish, preventing formation of mold and mildew, and preventing structural damage to the underlying building wall and exterior surface finish. In other embodiments, lightweight composite panels, particularly lightweight composite plaster panels, can be used to make interior walls and ceilings in place of gypsum board or lath and plaster.

[0104] The lightweight composite panels are typically rectangular in shape, with a constant cross sectional thickness. The lightweight composite panel can have multiple uses, including for interior walls that are exposed to moisture, providing a substrate to which tiles,- Page 25 - Docket No. 23807.1astones, 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, thin brick, 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 bleed layer to facilitate removal of moisture between the lightweight composite panels and exterior wall structures. The lightweight composite panels can also be modified to include a plaster layer, such as for interior panels that replace conventional gypsum board.

[0105] The lightweight composite panels can be fastened to wall or roof structures of a building using mechanical fasteners and adhesives known in the art, such as wood screws, sheet metal screws, nails, rivets, and construction adhesive. Mechanical fasteners 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 wall or roof structures.

[0106] To prevent screws from tearing through the exterior fiber mesh reinforced cementitious layer, screws can be used with enlarged washers having high surface area to distribute the pressure or load over a high surface area of the lightweight composite panels. Specialized washers with penetrating prongs can be used (e.g., with screws) 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. The penetrating prongs can have a length so that the washers lie flush with or just below the surface of the exterior fiber mesh reinforced cementitious layer. A patch coating can be applied over the washers to fill any indentations caused by the washers or other mechanical fasteners.

[0107] Figures 4A-4C illustrate a fastener assembly 400 comprising a screw 402 and specialized washer 404 with enlarged surface area and penetrating prongs 410 for attaching a lightweight composite panel 420 to a stud 428 or other structural element (e.g., OSB sheathing). The penetrating prongs 410 help fix the washer 404 in place relative to the lightweight composite panel 420 and prevent rotation of the washer 404 when the screw 402 is being driven into the stud 428 or other structural element of a wall or roof structure and add additional lateral strength between the washers 404 and the lightweight composite building panel 420. The penetrating prongs 410 can also be designed to abut the underlying- Page 26 - Docket No. 23807.1astud 428 or other structural element and act as a stop to prevent the washer 404 from being driven too far into the lightweight composite panel 420 and undesirably crushing or fracturing the exterior fiber mesh reinforced cementitious (or other protective) layer 422, which could reduce the strength of an interior or exterior wall structure or roofing deck.

[0108] Figure 4A more particularly illustrates the use of a specialized fastener assembly 400 comprising a screw 402 and specialized washer 404 having a body 406 of enlarged diameter, a concave interior portion 408, and a plurality of penetrating prongs 410 extending laterally from the washer body 406. Although the specialized washer 404 in this embodiment is illustrated as having a circular washer body 406, 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.

[0109] The penetrating prongs 410 are designed to penetrate through and become embedded within a lightweight composite panel 420, including though the exterior fiber mesh reinforced layer 422, at least partially through the polymer foam core 424, and optionally through the interior fiber mesh reinforced layer 426 so as to make abutment with a stud 428 or other structural element of a wall or roof frame (not shown). The penetrating prongs 410 help retain the specialized washers 404 in a desired position relative to the lightweight composite panel 420 and prevent rotation while the screw 402 is being driven through the lightweight composite panel 420 and into the underlying stud 428 or other structural element of a wall or roof frame. The penetrating prongs 410 can also provide a load spreading / pressure spreading effect to distribute normal and lateral pressure from the screw 402 and washer body 406 to the prongs 410. The specialized washer 404 and penetrating prongs 410 provide greater lateral tension of the screw and washer assembly relative to the lightweight composite panel 420, thereby increasing the overall shear strength of a wall or roof structure.

[0110] Figure 4B is a bottom perspective view and Figure 4C is a top perspective view of the specialized washer 404, which more particularly illustrate features of the specialized washer 404. The washer body 406 can have an enlarged diameter in order to provide higher surface area and increase contact between the specialized washer 404 and an adjacent fiber reinforced cementitious layer of a lightweight composite panel. The washer body 406 can have a concave interior portion 408, which permits an outer rim 412 to become substantially flush with and the concave interior portion 408 to advance below the adjacent fiber reinforced cementitious layer when used to attach a lightweight composite panel to a wall- Page 27 - Docket No. 23807.1aor roof structure. This allows the concave interior portion 408 to partially compress the interior foam core 424 and exterior fiber reinforced cementitious layer 422 of the lightweight composite panel to provide firm and reliable attachment of the panel to the wall or roof structure. The washer body 406 can include a countersink 414 that accommodates the head 403 of the screw 402 so that the screw head 403 does not protrude beyond the surface of the washer body 406 when driven into a stud 428 or other structural element of a wall or roof frame.[OHl] The length of the penetrating prongs 410 can be selected to determine and limit how far the concave interior portion 408 of the washer body 406 is able to advance into and compress the lightweight composite panel 420. The penetrating prongs 410 can advantageously have a length in order to penetrate all the way through the lightweight composite panel 420 and make contact with the stud 428 or other structural element. In this way the penetrating prongs 410 can act as a stop that limits how far the specialized washer 404 can be driven toward and into the lightweight composite panel 420. Providing a stop prevents the specialized washer 404 from being driven too far into the lightweight composite panels 420, thereby preserving the structural integrity and strength of the exterior fiber mesh reinforced cementitious layer 422 adjacent to the specialized washer 404. This preserves and maximizes the overall strength, including shear strength, of the wall structure.

[0112] In some embodiments, it may be desirable for the length of the penetrating prongs 410 to be slightly less than the cross-sectional thickness of the lightweight composite panel 420 in order to superficially compress, but not damage, the exterior fiber mesh reinforced cementitious layer 422 toward the polymer foam core 424 to thereby increase the compressive force of the washer 404 bearing against the lightweight composite panel 420. This can increase the overall fixation strength of the fastening assembly 400.A. Lightweight Composite Building Panels With Incorporated Drainage Layer

[0113] In order for lightweight composite building panels to facilitate removal of moisture between the panels and underlying sheathing or other structural elements, such as where the panels are used as underlayment or backer board to applied a desired exterior finish of a building, the lightweight composite panels (core composite panel structures) described herein are modified to incorporate a drainage layer that faces wall sheathing or other underlying structural elements. The drainage layer is typically a made from a polymer material and includes passages and gaps that facilitate removal of moisture, such as diffusion of water vapor and / or drainage of liquid water.

[0114] Figures 5 A and 5B illustrate lightweight composite building panels 500a, 500b- Page 28 - Docket No. 23807.1afor exterior use that include a core composite panel structure 502 and incorporated drainage layers 504a, 504b made of polymer or other material that provides a pathway for removal of moisture from between the lightweight composite building panels 500a, 500b and sheathing or other structural elements of an exterior wall or roof structure (not shown). The drainage layer 504a, 504b 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 504a, 504b include physical gaps to promote drainage and removal of moisture that might otherwise collect between the lightweight composite building panels 500a, 500b and the underlying wall or roof structure to which they are attached.

[0115] The drainage layers 504a, 504b can be attached to a surface of the core composite panel structures 502a, 502b using adhesives known in the art. In some embodiments, the drainage layers 504a, 504b can be adhered to the core composite panel structures 502a, 502b using a standard polymer modified mortar, such as the cementitious composition used to form the outer surface layers of the core composite panel structures 502a, 502b. In some embodiments, the protective layer on the side of the core composite panel structure 502 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.

[0116] The surface of the lightweight composite building panels 500a, 500b opposite the drainage layers 504a, 504b can be a fiber mesh reinforced cementitious layer that can be used to apply a desired exterior surface finish, such as stucco, thin bricks, tiles, stone veneers, shingles, and the like. The lightweight composite building panels 500a, 500b 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.

[0117] Figures 6A-6D illustrate alternative embodiments of drainage layers 600a, 600b, 600c, 600d, 600e that provide gaps or channels and that can be adhered or attached to the interior side of a core composite panel structure to create a lightweight composite building panels to which an exterior surface finish, such as stucco, thin bricks, tiles, stone veneers, shingles, wood shakes, metal cladding, and like can be attached. The drainage layers 600a, 600b, 600c, 600d, 600e are not required to bear structural loads because the lightweight composite building panels, having the strong core composite panel structure described herein, can be screwed, nailed, glued, or otherwise secured to the underlying wall or roof- Page 29 - Docket No. 23807.1astructure so as to bear the entire load, including loads from applied exterior finishes, such as stucco, thin brick, stone, tiles, and the like. The only function of the drainage layers 600a, 600b, 600c, 600d, 600e is to provide gaps that facilitate removal of moisture from between an outer wall of a building and lightweight composite panels.

[0118] 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.

[0119] 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 1 / 4 inch, maintaining an air gap between the panel and substrate. An illustrations of a recommended configuration for the applied dots or dimples are as follows:• Dot height: 1.5-6 mm (1 / 16 inch to 1 / 4 inch);• Spacing: 2 inches to 4 inches on center. Even spacing allows for horizontal or vertical panel installation in the field;• Coverage: full panel back except edges within 2 inches of perimeter

[0120] Example materials that can be used to form the dots or dimples can have the following characteristics:• Preferred: Ik or 2k polyurethane (moisture or chemically cured);• Alternatives: high-density silicone (RTV) or hot-melt adhesives (if appropriate for temperature range);• Adhesive should exhibit adequate bond panel surface, maintain shape under load, and resist water, freeze / thaw, and thermal cycling.

[0121] The following are example performance goals for drainages layers generally, and applied dots or dimples specifically:• Maintain continuous drainage channel per ASTM E2273 principles;• Sustain compression resistance under fastener tension and cladding load;• Support full panel structural and moisture management performance without compromising finish integrity.- Page 30 - Docket No. 23807.1a

[0122] The lightweight composite building panels are typically rectangular in shape, with a constant cross sectional thickness. The lightweight composite building 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 paneling that covers and / or replaces OSB panels, as a substrate for stucco, thin brick, 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.

[0123] The lightweight composite building panels can be used in place of conventional wallboards, panels, sheathing, and cladding, including for a variety of uses such as interior wallboard, backer boards for tile and other interior finishes, including those exposed to moisture, exterior wall sheathing and finishes applied thereto, floor underlayment, soffits, roofing decks and roof elements applied thereto, shaft liners, and the like.

[0124] The lightweight composite building panels can be cut, drilled, and fastened to structural elements of buildings, such as wall frames comprising wooden or metal studs, roof frames comprising boards, studs, or trusses, floor joists, concrete floors, foundations, and the like. Because both sides of the core composite panel structure comprise a fiber mesh reinforced cementitious composition, the lightweight composite building panels are strong and can support relatively heavy loads, such as thin bricks, wall tiles, stone veneers, stucco, roofing tiles, shingles, metal cladding, wood shakes, and other finishes applied thereto and / or fixtures or other items using nails, screws, adhesives, and other fasteners known in the art.

[0125] In some embodiments, lightweight composite building panels can be used as backing for exterior finishes, such as stucco, thin bricks, stone veneers, or other finishes. For this reason, the lightweight composite building panels, including for application of a surface finish, include a drainage layer, such as an uncoupling membrane, drainage plane, rain screen, dimple board, factory-applied dimples or dots, or bleed layer, which provides gaps and channels between the lightweight composite panels and the underlying building surface to permit moisture (e.g., from ingress or condensation) to collect, drain and / or evaporate, thereby protecting the outer surface finish, preventing formation of mold and mildew, and preventing structural damage to the underlying building wall and exterior surface finish.

[0126] The lightweight composite panels can be fastened to wall or roof structures of a- Page 31 - Docket No. 23807.1abuilding using mechanical fasteners and adhesives known in the art, such as wood screws, sheet metal screws, nails, rivets, and construction adhesive. Mechanical fasteners 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 wall or roof structures.

[0127] In some embodiments, the lightweight composite building panels can be used as an intermediate layer between exterior sheathing (e.g., OSB panels) and an applied finish, such as stucco, thin bricks, stone veneers, tiles, shingles, cladding, and the like. The drainage layer facilitates removal of moisture between the lightweight composite building panels and sheathing or other underlying structural elements of an exterior wall or roof structure.

[0128] In general, all drained enclosure systems, whether walls, basements, or roofs, are typically required to have a screen or cladding, a drainage gap (often a clear air space), a drainage plane (a water repellent plane), flashing at the base to direct water outwards, and drain holes (weep holes) to allow water out of the drainage gap. Water flows down under the force of gravity clinging to a surface, e.g., the interface between the back of the cladding and the airspace or the interface between roofing paper and a roof shingle. It has been shown that water can drain through very small gaps (e.g., 1-2 mm), even the small gap between two sheets of building paper.

[0129] Reference is made to Figures 7A-7C, which illustrate exterior building elements or finishes 700 attached to an underlying wall 702 of a building. They illustrate how a gap 704 is provided between the exterior building elements or finishes 700 and the underlying building wall 702. This gap 704 permits moisture that may have entered this region to be drained and / or evaporated away from the underlying building wall 702. Figure 7A in particular illustrates how condensed liquid water 706 can drain from the bottom of the gap 704 and how water vapor 708 can vent from the top of the gap 704. Figure 7B illustrates how water that may penetrate through an exterior finish 700 can drain though the gap 704. Figure 7C illustrates how water that may penetrate through an exterior finish 700 can drain though the gap 704 and / or how water vapor can diffuse through the exterior finish 700.

[0130] The lightweight composite building panels can be attached to wall or roof structures, including sheathing and other structural elements using known attachment means, including screws, nails, and adhesives. In some embodiments, specialized fasteners can be used, as illustrated in Figures. 4A-4C described above, to attach lightweight composite building panels to wall or roof structures. The specialized fasteners comprise screws and enlarged washers having high surface area to distribute the pressure or load over- Page 32 - Docket No. 23807.1aa high surface area of the lightweight composite building panels.

[0131] In some embodiments, sealing one or more joints or seams between adjacent lightweight composite building 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 or roofing deck face and comers. In addition, joints, seams, openings, or gaps between lightweight composite building 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 building panels to the exterior wall or roof structure, and over any joints or seams, fiber mesh tape, polyurethane, or other exposed sealants on or in the exterior wall or roof structure.

[0132] Figure 8 illustrates an example use of lightweight composite building panels disclosed herein by direct application of a stucco finish. Figure 8 more particularly illustrates a stucco system 800 that includes a lightweight composite building panel 802, which includes an exterior-facing fiber mesh reinforced cementitious (or other protective) layer as a bonding substrate. The lightweight composite building panel 802 can be fastened to a wall or roof structure (not shown) by means of screws 804. Two of the screws 804 are shown covered by a patch coat 806 (e.g., thin set mortar or fine-sanded stucco) to create a smooth surface. A stucco finish 808 is applied over the fiber mesh reinforced cementitious (or other protective) layer 802 and patch coat 806. Both cement-based stucco and acrylic stucco can readily adhere directly to the fiber mesh reinforced cementitious (or other protective) layer 802 and patch coat 806. A primer is typically not required when using acrylic-based stucco, although a primer can be used if desired. Any primer known in the art for acrylic-based stucco can be used.

[0133] Figure 9 is a perspective view of a mockup that illustrates the use of lightweight composite building panels to form a backer board or underlayment for direct application of a stucco finish. It will be appreciated that other finishes, such as thin bricks, stone veneers, tiles, shingles, and the like can be attached to the disclosed lightweight composite building panels. Figure 9 more particularly illustrates another example stucco system 900 according to the disclosure. A difference between this embodiment and that of Figure 8 is that the- Page 33 - Docket No. 23807.1aembodiment of Figure 9 utilizes screws 910 pared with enlarged washers 912 to fasten a pair of adjacent lightweight composite building panels 908a, 908b to the exterior wall structure 902, which is formed using studs 904 and OSB sheathing 906.

[0134] A vertical concourse of screws 910 and enlarged washers 912 are used to interconnect adjacent lightweight composite building panels 908a, 908b fastened to the OSB sheathing 906. A vertical strip of fiber mesh tape 930 is placed over the vertical concourse of screws 910 and enlarged washers 912 and a portion of the exterior-facing fiber reinforced (or other protective) layers of the adjacent lightweight composite building panels 908a, 908b, followed by applying a vertical strip of an appropriate seam coat (e.g., thin set mortar or fine-sanded stucco) 932 over the fiber mesh tape 930, screws 910 and enlarged washers 912, and a portion of the exterior-facing fiber reinforced (or other protective) layers to further tie the adjacent lightweight composite building panels 908a, 908b together. This further helps prevent separation and potential formation of cracks in the stucco finish 928 at the joint between the adjacent lightweight composite building panels 908a, 908b. The vertical strip of seam coat 932 also forms a more uniform surface to which the stucco finish 928 can be applied.

[0135] The example stucco system 900 also includes first and second comers 916, 918 formed between adjacent lightweight composite panels 908 positioned at 90° angles. The first corner 916 is protected by fiber mesh 920 and a first corner layer of an appropriate seam coat (e.g., thin set mortar or fine-sanded stucco) 922 in which the fiber mesh 920 is embedded. The second corner 918 is protected by a rigid comer bend 924, which can be made of galvanized steel or a plastic comer bend with integrated mesh, and a second corner layer of seam coat 926 covering the corner bend 924. It will be understood that the fiber mesh 920 and metal corner bend 924 are alternative embodiments and need not be included in the same embodiment. Rather, some embodiments may use the fiber mesh 920 and other embodiments may use the metal corner bend 924 (e.g., to provide greater protection against mechanical damage caused by blunt force to wall corners). One or more layers of stucco finish 928 (cement- or acrylic-based) is applied over the exterior-facing fiber mesh reinforced cementitious layers, vertical strip of seam coat 932, and first and second comer layers of seam coat 922, 926.

[0136] Figure 10 illustrates an exterior wall 1000 that includes lightweight composite building panels 1002 attached over an exterior wall structure (not shown) and various exterior finishes applied to the lightweight composite building panels 1002. These include a stucco finish 1004, stone veneers 1006, and tiles 1008 applied over different portions of- Page 34 - Docket No. 23807.1athe lightweight composite building panels 1002. A layer of fiber mesh 1010 and a layer of an appropriate bonding layer 1012 (e.g., thin set mortar or fine-sanded stucco) covering the fiber mesh 1010 is applied over a portion of lightweight composite building panels 1002 to which the various finished are applied. The stucco finish 1004 (cement- or acrylic-based) can be applied directly over the bonding layer 1012. The stones veneers 1006 can be adhered to the bonding layer 1012 using thin set mortar (not shown) and / or an adhesive. The tiles 1008 can be adhered to the bonding layer 1012 using thin set mortar (not shown) and / or an adhesive.

[0137] Figure 11 illustrates exterior sheathing or cladding 1100 that includes thin bricks 1102 applied to an exterior surface of one or more lightweight composite panels 1104 to provide an exterior finish of a wall. The thin bricks 1102 can be factory installed to form exterior sheathing 1100 with a pre-applied finish, or they can be applied to the lightweight composite panels 1104 after placement on a wall or roof structure to form the exterior finish. In some embodiments, the exterior sheathing or cladding 1100 can omit the drainage layer.

[0138] Another embodiment of the disclosed lightweight composite building panels is their use as roof sheathing to form a roofing deck to which roofing tiles, shingles, metal cladding, and / or wood shakes can be applied to form a finished roof of a building. The lightweight composite building panels have high strength and rigidity notwithstanding their low density and lightweight owing to the composite structure of the foam layer and the fiber mesh reinforced cementitious (or other protective) layers, which strongly adhere to the foam layer. A roofing system can include roofing joists, trusses to which lightweight composite panels are fixedly attached, such as by constructure adhesive, roofing screws, or roofing nails. The lightweight composite panels are sufficiently strong that they can support the weight of workers standing on top of the roof, as well as the finish roofing elements, when attached to roofing joists, trusses, and joints with typical spacing.B. Lightweight Composite Plaster Panels

[0139] In order for lightweight composite plaster 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 panels (core composite panel structures) described herein are modified to include a plaster layer applied over at least one of the fiber mesh reinforced cementitious (or other protective) layers. The plaster layer can be generally white in color, although other colors are possible if desired.

[0140] Lightweight composite plaster panels can include a light colored (e.g., white or- Page 35 - Docket No. 23807.1aoff white) plaster layer bonded 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 plaster panels the appearance of plasterboard without paper. Because lightweight composite plaster 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 panels. The lightweight composite plaster 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 lightweight composite wallboards to which an exterior finish is applied, or to make shaft liners.

[0141] The lightweight composite plaster panels include a lightweight foam core sandwiched between two fiber mesh reinforced cementitious (or other protective) layers, but with an additional plaster coating applied on at least one protective layer to provide a plaster finish to yield panels that can substitute for gypsum drywall panels. 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 lightweight 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 lightweight composite plaster panels can also include bevels (e.g., 2 or 4) to permit placement of multiple adjacent lightweight composite plaster panels, followed by application of dry wall patch (taping and mudding) to hide the joints. Specialized connectors, such as washers with enlarged surfaces and penetrating prongs as described above relative to Figures 4A-4C, can be used to join adjacent lightweight composite plaster panels together.

[0142] Reference is made to Figures 12-16B, which illustrate example embodiments of lightweight composite plaster panels of the disclosure. Figure 12 illustrates the layered structure of an example lightweight composite plaster panel 1200. The lightweight composite plaster panel 1200 comprises the core composite panel structure, including a foam core 1210 sandwiched between a first fiber mesh reinforced cementitious (or other protective) layer 1220 and a second fiber mesh reinforced cementitious (or other protective) layer 1230. A plaster layer 1240 is formed over the second fiber mesh reinforced cementitious (or other protective) layer 1230, 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- Page 36 - Docket No. 23807.1awallpaper. The plaster layer 1240 in this embodiment is shown as having a textured surface that provides the look of rough plaster. It will be appreciated that the plaster layer 1240 can have any desired surface finish, including smooth to very smooth, including a level 5 finish, which is a substantial improvement over traditional gypsum drywall panels.

[0143] The fiber mesh reinforced cementitious layers 1220, 1230 provide several advantages. The textured surface of the second fiber mesh reinforced cementitious layer 1230 can enhance the bond strength of the plaster layer 1240 and prevent delamination. Because the first fiber mesh reinforced cementitious layer 1220 does not include a finish layer it can have a textured surface that facilitates adhesion of the lightweight composite plaster panel 1200 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 1220, 1230 provide high strength, which permits the lightweight composite plaster panel 1200 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 1220, 1230.

[0144] Figures 13A-13C illustrate another embodiment of a lightweight composite plaster panel 1300 made from a core composite panel structure with a smooth plaster layer formed over the exposed or show side. The lightweight composite plaster panel 1300 comprises the core composite panel structure, including a foam (e.g., polymer) core 1310 sandwiched between first and second fiber mesh reinforced cementitious (or other protective) layers 1320, 1330. A plaster layer 1340 is formed over the second fiber mesh reinforced cementitious (or other protective) layer 1330, which forms the show side that will be visible as the interior wall surface before applying a desired finish, such as paint or wallpaper. The plaster layer 1340 in this embodiment has a smooth surface finish. It will be appreciated that the plaster layer 1340 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.

[0145] The textured surface of the second fiber mesh reinforced cementitious layer 1330 can enhance the bond strength of the plaster layer 1340, which prevents delamination. The first fiber mesh reinforced cementitious (or other protective) layer 1320 can have a textured surface that facilitates adhesion of the lightweight composite plaster panel 1300 to wall frame studs, ceiling joists, or other underlying structure. The first and second fiber mesh reinforced cementitious (or other protective) layers 1320, 1330 provide high strength, which- Page 37 - Docket No. 23807.1apermits the lightweight composite plaster panel 1300 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 1320, 1330.

[0146] Figures 14A-15B illustrate lightweight composite plaster panels 1400, 1500 having beveled edges. Figure 14A schematically illustrates a lightweight composite plaster panel 1400 having four beveled edges 1442, one in each of the four sides, and a plaster layer 1440 covering the entire upper surface, beveled edges 1442, and side ends 1446. The plaster layer 1440 over the beveled edges 1442 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 1442 to provide the beveled edges 1442 with a smooth finish and additional strength.

[0147] Figure 14B is a side cross-sectional view, and Figure 14C is an exploded view, showing the layered structure of an embodiment of a lightweight composite plaster panel 1400. As illustrated in Figure 14B, the lightweight composite plaster panel 1400 includes a foam (e.g., polymer) core 1410, a first fiber mesh reinforced cementitious (or other protective) layer 1420 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1430 on an exterior side, and a plaster layer 1440 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1430. The lightweight composite plaster panel 1400 includes beveled edges 1442, with a beveled portion of the foam core 1410 being partially covered by a believed portion of the second fiber mesh reinforced cementitious layer 1430, which in turn is covered by a beveled portion of the plaster layer 1440. In this way, the beveled edges 1442 can have similar strength as the nonbeveled portion of the lightweight composite plaster panel 1400, which permits using nails, screws, or other fastening means to fasten the lightweight composite plaster panel 1400 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1442.

[0148] Figure 14C is an exploded view of the lightweight composite plaster panel 1400 that more particularly illustrates the layered structure. The lightweight composite plaster panel 1400 includes a polymer foam core 1410, a first fiber mesh reinforced cementitious (or other protective) layer 1420, which can include a first cementitious layer with embedded first fiberglass mesh (not shown), a second fiber mesh reinforced cementitious (or other protective) layer 1430, which can include a second cementitious layer with embedded second fiberglass mesh (not shown), and a plaster layer 1440 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1430. The lightweight composite- Page 38 - Docket No. 23807.1aplaster panel 1400 also includes beveled edges 1442, which includes a beveled portion 1412 of the polymer foam core 1410 partially covered by a beveled portion 1432 of the second fiber mesh reinforced cementitious (or other protective) layer 1430, which are both covered by the beveled portion 1442 of the plaster layer 1440.

[0149] Figure 15A is a side cross-sectional view, and Figure 15B is an exploded view, showing the layered structure of another embodiment of a lightweight composite plaster panel 1500. As illustrated in Figure 15 A, the lightweight composite plaster panel 1500 includes a foam (e.g., polymer) core 1510, a first fiber mesh reinforced cementitious (or other protective) layer 1520 on an interior side, a second fiber mesh reinforced cementitious (or other protective) layer 1530 on an exterior side, and a plaster layer 1540 formed over the second fiber mesh reinforced cementitious (or other protective) layer 1530. The lightweight composite plaster panel 1500 includes beveled edges 1542, with a beveled portion of the foam core 1510 being entirely covered by a believed portion of the second fiber mesh reinforced cementitious layer 1530, which in turn is covered by a beveled portion of the plaster layer 1540. In this way, the beveled edges 1542 can have the same reinforcement and strength as the non-beveled portion of the lightweight composite plaster panel 1500, which permits using nails, screws, or other fastening means to fasten the lightweight composite plaster panel 1500 to wall frame studs, ceiling joists, or other structural elements through the beveled edges 1542.

[0150] Figure 15B is an exploded view of the lightweight composite plaster panel 1500 that more particularly illustrates the layered structure. The lightweight composite plaster panel 1500 includes a polymer foam core 1510, a first fiber mesh reinforced cementitious layer 1520, which includes a first cementitious layer 1520a with embedded first fiberglass mesh 1520b, a second fiber mesh reinforced cementitious layer 1530, which includes a second cementitious layer 1530a with embedded second fiberglass mesh 1530b, and a plaster layer 1540 formed over the second fiber mesh reinforced cementitious layer 1530. The lightweight composite plaster panel 1500 also includes beveled edges 1542, which includes a beveled portion of the polymer foam core 1510 entirely covered by a beveled portion of the second fiber mesh reinforced cementitious layer 1530, which is entirely covered by a beveled portion of the plaster layer 1540.

[0151] In some embodiments, it may be desirable to apply and finish the plaster layer of the lightweight composite plaster panels disclosed herein in a manner that provides what is known in the industry as a “level 5” finish, or “drywall finish level 5”. A level 5 finish is defined by the Gypsum Association, the trade association for drywall professionals. The- Page 39 - Docket No. 23807.1aGypsum Association has codified a set of professional standards that define the process of finishing drywall into five distinct levels. The following definitions are given for comparison. A level 0 finish means that no drywall finishing of any type has been done. At this level, the drywall boards are simply fastened to the walls or ceiling. A level 1 finish means that dry wall joint tape has been embedded in the joint compound at the seams or joints, with no further finishing. A level 2 finish means that a skim coat of joint compound has been applied over the tape and to cover drywall screw holes. A level 3 finish means that a drywall finisher has applied a coat of joint compound to the tape and screws. Walls that will receive a heavy texture can end at this level, as progressing beyond this level of smoothness is unnecessary since texturing will produce a finish that is rougher than level 3. A level 4 finish is the classic drywall finish. This is achieved by applying another coat of joint compound to the tape and screws and sanding the dried compound. A level 4 finish is typically used when a surface is painted or covered with wallpaper. A level 5 finish is the highest possible level of drywall finishing and involves applying a skim coat, if applicable. A level 5 finish is achieved by applying another skim coat of joint compound (or mud) to a level 4 finish and then fine sanded. A level 5 finish is desirable when the applied finish will have glossy, enamel, or non-textured flat paint or when the light will be angled low enough to highlight bumps and depressions.

[0152] A level 5 finish is a premium finish that typically commands a much higher cost than lower level finishes. Providing a lightweight composite plaster panel having a plaster coating that already provides a level 5 finish can eliminate the many steps and time required to prepare ordinary drywall to have a level 5 finish, particularly the need to apply a skim coat over the exposed paper surfaces of gypsum panels forming a wall or ceiling. This saves labor costs and time, including the time required for each coat of joint compound to dry and then be sanded.

[0153] Figure 16A illustrates two lightweight composite plaster panels 1600 positioned side-by-side and abutting each other, each having a plaster layer 1602a, 1602b and beveled edges 1642a, 1642b that are aligned to facilitate application of tape and dry wall patch to hide the seam and join the lightweight composite dry wall boards 1600 together, as illustrated in Figure 16B. Figure 16A shows the beveled edges 1642a, 1642b covered by a portion of the plaster layers 1602a, 1602b, while Figure 16B shows the beveled edges 1642a, 1642b hidden beneath a plaster coating (e.g., drywall patch or joint compound) 1644 such that the two lightweight composite plaster panels 1600 have been joined together to yield a finished, seamless plaster surface finish. A level 5 finish can be achieved in a minimal number of- Page 40 - Docket No. 23807.1asteps by taping and plastering only the beveled edges 1642a, 1642b, followed by sanding the joint. Skim coating and sanding of the non-beveled portions of the plaster layers 1602a, 1602b is not required if they already have a factory applied level 5 finish.

[0154] Figure 17 illustrates an example beveling apparatus 1700 with a beveling tool 1702 used to grind or cut bevels into the sides of a partially constructed core composite panel structure 1704 prior to applying the second fiber mesh reinforced cementitious (or other protective) layer and the plaster layer. As illustrated in Figures 15A and 15B, the bevels can be formed by removing a portion of the foam core 1510 to form beveled regions, which can be covered by the second fiber mesh reinforced cementitious layer 1530 to maximize strength in the beveled region, and then be covered by the plaster layer 1540 to form the finished beveled edges 1532. Thus, the beveling apparatus can make beveled edges in an uncoated side of the polymer foam core 1510, followed by applying the second fiber mesh reinforced cementitious layer 1530 on the beveled side, which is allowed to at least partially harden, followed by applying the plaster layer 1540 over the second cementitious layer 1530 to form composite layered beveled edges 1542. The composite layered beveled edges 1542 provide substantially greater strength for receiving screws, nails, or other mechanical fastening means known in the art.

[0155] 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.

[0156] 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 (AI2O3) 1-3%- Page 41 - Docket No. 23807.1aSilicon 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)

[0157] 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.

[0158] 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 wallboard (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.

[0159] 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 lightweight 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 lightweight composite plaster panels.

[0160] Advantages of the lightweight composite plaster panels disclosed herein include: being lightweight (i.e., approximately 1 / 3 the weight of gypsum drywall panels and approximately 1 / 6 the weight of cement board); 100% waterproof as a result of the core- Page 42 - Docket No. 23807.1abeing 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.

[0161] Other advantages include the following:

[0162] Benefits from being lighter weight than dry wall: a. delivery to site is cheaper; can ship 3 times more per truckload to the site; b. easier to carry panels around job site because 1 / 3 the weight; c. lower labor due to light weight; doesn’t require two people to carry and hang panels.

[0163] Benefit from being waterproof: c. no shrinkage from moisture on site (meaning if it rains on a pile of drywall awaiting use, they often have to throw away the top layer, or some of rest if water entered sides); d. no mold risk, and less likely to have to be tom out and replaced if there is a leak in the house.

[0164] Benefits from just not being dusty gypsum: c. Less likely to crack or break if dropped; d. no gypsum dust.

[0165] Benefits from insulation: c. four times higher R-value; d. Some sound reduction.

[0166] Stronger: d. less likely to be damaged during construction transportation and handling; e. advantages in roofing applications (discussed below); f. performs as a structural panel for prescriptive braced walls or shear walls.

[0167] Weather resistant: b. very low freeze and thaw deformation, rate of 0.014% (relevant to outdoor applications).Additional Terms & Definitions

[0168] While certain embodiments of the present disclosure have been described in detail, with reference to specific configurations, parameters, components, elements,- Page 43 - Docket No. 23807.1aetcetera, the descriptions are illustrative and are not to be construed as limiting the scope of the claimed invention.

[0169] 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.

[0170] In addition, unless otherwise indicated, numbers expressing quantities, constituents, distances, or other measurements used in the specification 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 in the specification and claims, 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.

[0171] 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.

[0172] 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.

[0173] 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.- Page 44 - Docket No. 23807.1a

Claims

CLAIMS1. A lightweight composite panel, comprising: a polymer foam core having a first surface, a second surface opposite the first surface, a first side edge forming a perimeter of the first surface, a second side edge forming a perimeter of the second surface, and a side surface extending between the first and second side edges; a first protective layer selected from a first fiber reinforced cementitious layer or first thermoset polymer layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective layer selected from a second fiber reinforced cementitious layer or second thermoset polymer layer formed over and covering at least a portion of the second surface of the polymer foam core, wherein the first or second fiber reinforced cementitious layer, when included, comprises fiber reinforcement embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate, wherein the first or second thermoset polymer layer, when included, comprises polyurea or polyaspartic and is optionally fiber-reinforced.

2. The lightweight composite panel of claim 1, wherein at least one of the first or second fiber reinforced cementitious layers is included, wherein the fresh cementitious composition comprises mixture products of water, hydraulic cement, silicon dioxide, calcium oxide, iron oxide, gypsum hemihydrate, water-reducing agent, defoamer, styrene, and acrylic acid or polymer thereof, and optionally at least one supplementary cementitious material (SCM) selected from the group consisting of ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, and finely ground quartz.

3. The lightweight composite panel of claim 2, wherein the fresh cementitious composition comprises mixture products of: 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%- Page 45 - Docket No. 23807.1adefoamer 0.2-0.6% styrene 1-2% acrylic acid 1-2% water 15-22% of dry ingredients.

4. The lightweight composite panel of claim 2 or 3, wherein: the fresh cementitious composition further comprises at least one of natural hydraulic lime, calcium silicate, or expanded glass; the hydraulic cement comprises Portland cement, optionally interground with a mineral filler, optionally limestone; the silicon dioxide comprises ground quartz sand, optionally 150 mesh; the water-reducing agent comprises a carboxylic acid grafted multi-polymer; and the defoamer comprises polydimethylsiloxane.

5. The lightweight composite panel of any one of claims 1 to 4, wherein at least one of the first or second fiber reinforced cementitious layers is included and has a cross- sectional thickness in a range of about 0.5 mm to about 3 mm, or about 0.75 mm to about 2.5 mm, or about 1 mm to about 2 mm, or about 1.25 mm to about 1.75 mm.

6. The lightweight composite panel of any one of claims 1 to 5, wherein at least one of the first or second thermoset polymer layers is included and has a cross-sectional thickness in a range of about 1 mm to about 5 mm, or about 2 mm to about 4 mm.

7. The lightweight composite panel of any one of claims 1 to 6, wherein the lightweight composite panel is substantially flat or planar.

8. The lightweight composite panel of any one of claims 1 to 7, wherein the first and second protective layers are mechanically and / or chemically bonded, respectively, to the first and second surfaces of the polymer foam core.

9. The lightweight composite panel of any one of claims 1 to 8, wherein at least one of the first or second fiber reinforced cementitious layers is included and comprises fiber reinforcement selected from fiber mesh, alkali-resistant fiberglass mesh, embedded fibers, fabric, woven, scrim, felt, and non-woven, wherein the fiber reinforcement comprise at least one of plant fibers, polymer fibers, and inorganic fibers, which are selected from fibers or filaments formed from glass, basalt, rock wool, or carbon.

10. The lightweight composite panel of claim 9, wherein the first or second fiber reinforced cementitious layer has a textured exterior surface.

11. The lightweight composite panel of any one of claims 1 to 10, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded- Page 46 - Docket No. 23807.1apolystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamineformaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure.

12. The lightweight composite panel of any one of claims 1 to 11, further comprising a finish on or applied to the first or second fiber mesh reinforced cementitious layer, wherein the finish is selected from the group consisting of thin bricks, wall tiles, stone, stucco, roofing tiles, shingles, metal cladding, wood shakes, and combinations thereof.

13. A lightweight composite panel, comprising: a polymer foam core having a first surface, a second surface opposite the first surface, a first side edge forming a perimeter of the first surface, a second side edge forming a perimeter of the second surface, and a side surface extending between the first and second side edges; a first protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the second surface of the polymer foam core, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure, wherein each of the first and second protective fiber mesh reinforced cementitious comprises fiberglass mesh embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate.

14. A lightweight composite panel, comprising: a polymer foam core having a first surface, a second surface opposite the first surface, a first side edge forming a perimeter of the first surface, a second side edge forming a perimeter of the second surface, and a side surface extending between the first and second side edges; a first protective thermoset polymer layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective thermoset polymer layer formed over and covering at least a- Page 47 - Docket No. 23807.1aportion of the second surface of the polymer foam core, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure, wherein the first and second thermoset polymer layers are independently selected from polyurea and polyaspartic and are optionally fiber-reinforced15. A method of manufacturing a lightweight composite panel as in any one of claims 1 to 14, comprising: providing the polymer foam sheet having a first surface, a second surface opposite the first surface, a first side edge forming a perimeter of the first surface, a second side edge forming a perimeter of the second surface, and a side surface extending between the first and second side edges; forming the first protective layer selected from a fiber reinforced cementitious layer or thermoset polymer layer over to cover at least a portion of the first surface of the polymer foam sheet; and forming the second protective layer selected from a fiber mesh reinforced cementitious layer or thermoset polymer layer over to cover at least a portion of the second surface of the polymer foam sheet, wherein the first or second fiber reinforced cementitious layer, when included, comprises fiber reinforcement embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate, wherein the first or second thermoset polymer layer, when included, comprises polyurea or polyaspartic and is optionally fiber-reinforced.

16. The method of claim 15, wherein: at least one of the first or second fiber mesh reinforced cementitious layer is included and formed by applying a fiber sheet or mesh over a first or second surface of the polymer foam sheet, applying the fresh cementitious composition over the fiber mesh or sheet in order to contact the first or second surface of the polymer foam sheet and embed the fiber sheet or mesh within the fresh cementitious composition, and causing or allowing the fresh cementitious composition to harden, wherein the fresh cementitious composition comprises mixture products of water,- Page 48 - Docket No. 23807.1ahydraulic cement, silicon dioxide, calcium oxide, iron oxide, gypsum hemihydrate, waterreducing agent, defoamer, styrene, and acrylic acid or polymer thereof.

17. The method of claim 15 or 16, wherein the fresh cementitious composition comprises mixture products of: 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 15-22% of dry ingredients.

18. The method of any one of claims 15 to 17, wherein the fresh cementitious composition is applied by a waterfall machine or procedure, curtain coater, or enrobing coater / machine.

19. The method of any one of claims 15 to 18, wherein: at least one of the first or second thermoset polymer layers is included and formed by spray coating one or more layers of a curable resin to the first or second surface of the polymer foam sheet, optionally with a fiber sheet or mesh between first and second layers of the curable resin, and causing or allowing the curable resin to cure.

20. The method of any one of claims 15 to 19, further comprising smoothing the applied fresh cementitious composition before causing or allowing it to harden, and optionally cutting or trimming excess material from the lightweight composite panel.

21. A lightweight composite building panel, comprising: a core composite panel structure comprised of: a foam core having a first surface and a second surface opposite the first surface; a first protective layer selected from a first fiber reinforced cementitious layer, first thermoset polymer layer, or first magnesium oxide layer formed over and covering at least a portion of the first surface of the foam core; and a second protective layer selected from a second fiber reinforced- Page 49 - Docket No. 23807.1acementitious layer, second thermoset polymer layer, or second magnesium oxide layer formed over and covering at least a portion of the second surface of the foam core; and a drainage layer incorporated on a side of the core composite panel structure.

22. The lightweight composite building panel of claim 21, wherein at least one of the first or second fiber reinforced cementitious layers is included and comprises fiber reinforcement embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising mixture products of water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate.

23. The lightweight composite building panel of claim 22, wherein the fiber reinforcement is selected from fiber mesh, alkali-resistant fiberglass mesh, embedded fibers, fabric, woven, scrim, felt, and non-woven, wherein the fiber reinforcement comprise at least one of plant fibers, polymer fibers, and inorganic fibers, which are selected from fibers or filaments formed from glass, basalt, rock wool, or carbon.

24. The lightweight composite building panel of claim 22 or 23, wherein the fresh cementitious composition comprises mixture products of water, hydraulic cement, silicon dioxide, calcium oxide, iron oxide, gypsum hemihydrate, water-reducing agent, defoamer, styrene, and acrylic acid or polymer thereof, optionally at least one supplementary cementitious material (SCM) selected from the group consisting of ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, and finely ground quartz, and optionally at least one of natural hydraulic lime, calcium silicate, or expanded glass.

25. The lightweight composite building panel of any one of claims 22 to 24, wherein the fresh cementitious composition comprises mixture products of: 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 15-22% of dry ingredients.- Page 50 - Docket No. 23807.1a26. The lightweight composite building panel of any one of claims 22 to 25, wherein the at least one of the first or second fiber reinforced cementitious layers has a cross-sectional thickness in a range of about 0.5 mm to about 3 mm, or about 0.75 mm to about 2.5 mm, or about 1 mm to about 2 mm, or about 1.25 mm to about 1.75 mm.

27. The lightweight composite building panel of any one of claims 21 to 26, wherein at least one of the first or second thermoset polymer layers is included and comprises polyurea or polyaspartic and is optionally fiber-reinforced.

28. The lightweight composite building panel of claim 27, wherein the at least one of the first or second thermoset polymer layers has a cross-sectional thickness in a range of about 1 mm to about 5 mm, or about 2 mm to about 4 mm.

29. The lightweight composite building panel of any one of claims 21 to 28, wherein the drainage layer includes a polymer sheet, layer, dots, or dimples, applied, attached, or bonded to the side of the core composite panel structure that is configured to be placed against sheathing or other structural elements.

30. The lightweight composite building panel of claim 29, wherein the drainage layer is selected from an uncoupling membrane, drainage plane, rain screen, dimple board, factory-applied dots or dimples, and bleed layer.

31. The lightweight composite building panel of any one of claims 21 to 28, wherein the drainage layer includes or is provided by the first or second protective layer on the side of the core composite structure that is configured to be placed against sheathing or other structural elements and comprises a waterproof (e.g., polymer) material that is preformed or molded to include gaps and channels that function as the drainage layer to facilitate moisture removal.

32. The lightweight composite building panel of any one of claims 21 to 31, wherein the lightweight composite panel is substantially flat or planar.

33. The lightweight composite building panel of any one of claims 21 to 32, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure.

34. The lightweight composite building panel of any one of claims 21 to 33, further comprising a finish on or applied to the first or second protective layer, wherein the finish is selected from the group consisting of thin bricks, wall tiles, stone, stucco, roofing- Page 51 - Docket No. 23807.1atiles, shingles, metal cladding, wood shakes, and combinations thereof.

35. A lightweight composite building panel, comprising: a core composite panel structure comprised of: a polymer foam core having a first surface and a second surface opposite the first surface; a first protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the second surface of the polymer foam core, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenolformaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure, wherein each of the first and second protective fiber mesh reinforced cementitious comprises fiberglass mesh embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate; and a drainage layer incorporated on a side of the core composite panel structure.

36. A lightweight composite building panel, comprising: a core composite panel structure comprised of: a polymer foam core having a first surface and a second surface opposite the first surface; a first protective thermoset polymer layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective thermoset polymer layer formed over and covering at least a portion of the second surface of the polymer foam core, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenolformaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid- Page 52 - Docket No. 23807.1apolymer foam structure, wherein the first and second thermoset polymer layers are independently selected from polyurea and polyaspartic and are optionally fiber-reinforced; and a drainage layer incorporated on a side of the core composite panel structure.

37. A method of using a lightweight composite building panel as in any of claims 21 to 36, comprising: providing a wall or roofing structure that includes a wall or roof frame and sheathing attached to the wall or roof frame; and fastening the lightweight composite building panel to the sheathing so that the drainage layer is positioned between the sheathing and the core composite panel structure.

38. The method of claim 37, wherein the lightweight composite building panel is fastened to the wall or roofing structure using a plurality of fastener assemblies, each fastener assembly comprising a screw and an enlarged washer with multiple prongs that penetrate at least partially through and become embedded within the lightweight composite building panel.

39. The method of claim 38, wherein the enlarged washers of the fastener assemblies compress into the lightweight composite building panel, forming depressions therein, the method further comprising applying a seam coat or bonding layer over the fastener assemblies and filling in the depression to provide a smooth exterior surface.

40. The method of any one of claims 37 to 39, further comprising applying an outer surface finish to the lightweight composite building panel, wherein the outer surface finish is selected from stucco, thin bricks, stone veneers, tiles, roofing shingles, wood shakes, and metal cladding.

41. A composite plaster panel, comprising: a core composite panel structure comprised of: a foam core having a first surface and a second surface opposite the first surface; a first protective layer selected from a first fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the first surface of the foam core; and a second protective layer selected from a second fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the second surface of the foam core; and a plaster layer applied to and at least partially covering at least one side of the core- Page 53 - Docket No. 23807.1acomposite panel structure.

42. The composite plaster panel of claim 41, wherein at least one of the first or second fiber reinforced cementitious layers is included and comprises fiber reinforcement embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising mixture products of water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate.

43. The composite plaster panel of claim 42, wherein the fiber reinforcement is selected from fiber mesh, alkali-resistant fiberglass mesh, embedded fibers, fabric, woven, scrim, felt, and non-woven, wherein the fiber reinforcement comprise at least one of plant fibers, polymer fibers, and inorganic fibers, which are selected from fibers or filaments formed from glass, basalt, rock wool, or carbon.

44. The composite plaster panel of claim 42 or 43, wherein the fresh cementitious composition comprises mixture products of water, hydraulic cement, silicon dioxide, calcium oxide, iron oxide, gypsum hemihydrate, water-reducing agent, defoamer, styrene, and acrylic acid or polymer thereof, optionally at least one supplementary cementitious material (SCM) selected from the group consisting of ground granulated blast furnace slag (GGBFS), fly ash, natural pozzolan, silica fume, microsilica, metakaoline, ground glass, calcined clay, and finely ground quartz, and optionally at least one of natural hydraulic lime, calcium silicate, or expanded glass.

45. The composite plaster panel of any one of claims 42 to 44, wherein the fresh cementitious composition comprises mixture products of: 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 15-22% of dry ingredients.

46. The composite plaster panel one of claims 42 to 45, wherein the at least one of the first or second fiber reinforced cementitious layers has a cross-sectional thickness in a range of about 0.5 mm to about 3 mm, or about 0.75 mm to about 2.5 mm, or- Page 54 - Docket No. 23807.1aabout 1 mm to about 2 mm, or about 1.25 mm to about 1.75 mm.

47. The composite plaster panel of any one of claims 41 to 46, wherein at least one of the first or second thermoset polymer layers is included and comprises polyurea or polyaspartic and is optionally fiber-reinforced.

48. The composite plaster panel of claim 47, wherein the at least one of the first or second thermoset polymer layers has a cross-sectional thickness in a range of about 1 mm to about 5 mm, or about 2 mm to about 4 mm.

49. The composite plaster panel of any one of claims 41 to 48, wherein the plaster layer comprises reaction products of water, hydraulic cement, preferably white cement, calcium carbonate, aluminum oxide, silicon dioxide, cellulose ether, and latex.

50. The composite plaster panel of any one of claims 41 to 49, wherein the plaster layer comprises reaction products of hydraulic cement 30-50% calcium carbonate 40-70% aluminum oxide (AI2O3) 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)51. The composite plaster panel of any one of claims 41 to 50, wherein the composite plaster panel includes beveled edges, and wherein the plaster layer at least partially covers the beveled edges.

52. The composite plaster panel of any one of claims 41 to 51, wherein at least a portion of the plaster layer has a textured surface.

53. The composite plaster panel of any one of claims 41 to 52, wherein at least a portion of the plaster layer has a smooth surface, optionally a level 5 finish.

54. The composite plaster panel of any one of claims 41 to 53, wherein the composite plaster panel includes a single plaster layer, wherein a side of the composite plaster panel opposite the single plaster layer has a textured exterior surface.

55. The composite plaster panel of any one of claims 41 to 54, wherein the foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers- Page 55 - Docket No. 23807.1a(e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure.

56. The composite plaster panel of any one of claims 41 to 55, wherein the foam core comprises an inorganic foam material selected from the group consisting of silica gel, aerogel, silicate foams, urea-silicate foams, SiOC / SiC, ceramic foams, and refractory foams.

57. A composite plaster panel, comprising: a core composite panel structure comprised of: a polymer foam core having a first surface and a second surface opposite the first surface; a first protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the second surface of the polymer foam core, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenolformaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure, wherein each of the first and second protective fiber mesh reinforced cementitious comprises fiberglass mesh embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate; and a plaster layer applied to and at least partially covering at least one side of the core composite panel structure.

58. A composite plaster panel, comprising: a core composite panel structure comprised of: a polymer foam core having a first surface and a second surface opposite the first surface; a first protective thermoset polymer layer formed over and covering at least a portion of the first surface of the polymer foam core; and a second protective thermoset polymer layer formed over and covering at- Page 56 - Docket No. 23807.1aleast a portion of the second surface of the polymer foam core, wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenolformaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure, wherein the first and second thermoset polymer layers are independently selected from polyurea and polyaspartic and are optionally fiber-reinforced; and a plaster layer applied to and at least partially covering at least one side of the core composite panel structure.

59. A method of manufacturing a composite plaster panel as in any one of claims 41 to 58, comprising: providing the core composite panel structure; and forming the plaster layer over at least one side of the core composite panel structure, wherein the plaster layer is formed by applying a fresh plaster composition over at least one side of the core composite panel structure and causing or allowing the fresh plaster composition to harden or cure, wherein the fresh plaster composition comprises mixture products of water, hydraulic cement, preferably white cement, calcium carbonate, aluminum oxide, silicon dioxide, cellulose ether, and latex.

60. The method of claim 59, wherein the fresh plaster layer comprises mixture products of hydraulic cement 30-50% calcium carbonate 40-70% aluminum oxide (AI2O3) 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)- Page 57 - Docket No. 23807.1a

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