INSULATING BUILDING PANEL AND OTHER BUILDING COMPONENTS WITH INTEGRAL JOINERY

Related Application

This application is a continuation-in-part application of U.S. Patent Application Serial No. 07/959,226, filed November 13, 1992.

Technical Field The present invention is directed toward building components used for building construction and, more particularly, toward pre-manufactured building panels having integral joinery and improved strength, weight, and size characteristics.

Background of the Invention Recent changes in today's building industry have led to an increased demand by builders for pre-manufactured, or fabricated, building components. As an example, builders are now able to use pre-manufactured building panels for walls, roofs, floors, doors and other building components of a composite building structure. Such components are desirable because they greatly decrease the time and expense involved in constructing new building structures.

Although the pre-manufactured building components are desirable, they must meet the structural specifications required for the resulting composite building structure. The structural specifications are typically based on the combination of three structural criteria that are of primary interest: load bearing strength, shear strength, and total weight. These structural criteria must be considered when a plurality of the building components are joined together to build a structure that will be subjected to different forces including, for example, seismic forces and wind forces. Additional highly desirable and important characteristics of the building components include fire resistance, thermal efficiency, acoustical rating, water resistance, and rot and insect resistance.

Builders are facing increased demands to build stronger structures to withstand wind and seismic forces. High-rise and mid-rise buildings typically use a very strong and expensive "post and beam" frame construction for maximum resistance to wind and seismic forces. Conventional pre-manufactured construction panels are then secured to the post and beam frame. However, such post and beam construction is not cost effective for single story and low rise, multi-story buildings. In addition, the

post and beam frame and the pre-manufactured building components have experienced many thermal, acoustic, and durability drawbacks.

Thermally conductive materials such as solid wood, steel, or concrete are typically used to form the structural frame of buildings. These thermally conductive materials act as heat sinks, so a substantial amount, e.g.. over 50%, of a building's heat loss occurs through the frame. Additional heat losses occur through poorly insulated pre-manufactured building components, such as wall, roof and floor panels, attached to the frame.

The pre-manufactured building components have in the past had a variety of constructions in an effort to maintain strength and insulation capabilities. A common component is a laminated or composite panel. One such panel includes a core material of foam or other soft insulating material sandwiched between wood face sheets. These composite panels suffer from the disadvantages of being combustible, as well as inadequate sound barriers. These panels are also fairly expensive and subject to water damage, rot, decay, and insect attack. Attempts have been made to overcome such problems by adding a laminated skin to the outside of the wood face sheet. This additional layer, however, increases the expense and the weight of the panel. Accordingly, panels constructed in this manner are not deemed satisfactory in many modern building applications. In another known construction for building panels, a foam core is sandwiched between metal sheets. Decorative material is typically bonded to the outside of the metal sheets to make these building panels aesthetically pleasing. However, these panels are expensive and very sound transmissive. To reduce their sound transmission properties, an acoustical barrier is generally required on the inside metal sheet, thereby further increasing the cost of construction for such panels. The metal and foam panels are also susceptible to damage from thermal expansion. When the panel is installed on a building, the outside metal sheet is typically exposed to different thermal conditions than the inside metal sheet. The outside metal sheet expands or contracts at a rate different than the inside metal sheet, thus shear forces are exerted on the foam core. The conventional foam core is weak in shear, so it is highly susceptible to failure or breakdown under shear forces, which greatly reduces the structural integrity and effective life of the panel. As such, the metal and foam panels also are not suitable for load-bearing applications, and are classified as "non load-bearing panels." Concrete panels made from conventional concrete mix have also been used in building construction. These concrete panels, however, result in an inconsistent, often damp, surface having poor lamination bonding qualities. As a result,

laminated skin surfaces, such as veneer, phenolic, vinyl, or the like, cannot be sufficiently bonded to the inconsistent surface without considerable secondary preparation. A further drawback of the conventional concrete panels is the panels are very heavy and lack flexibility, and the thermal properties of the conventional concrete are very poor, even when a core is cast into the concrete panel.

The prior art construction panels are also designed to join to other building panels in different ways, but the resulting joint between the panels have major drawbacks. For example, construction panels having flat joining sides are adhered or bolted together with the flat joining sides abutting against each other. The flat joining sides are susceptible to damage from shear forces and bending forces exerted on the building panels, and often the joint between the panels loosen over time so gaps appear between the panels. Further, the abutting flat joining sides provide an area through which water can easily migrate. The result is a building structure that is susceptible to water damage. Other building panels have a single tongue on one side of the panel and a single groove on the opposite side of the panel. The single tongue or groove on one panel connects to a groove or tongue, respectively, on an adjacent panel. The resulting single tongue-and-groove joint, however, loosens over time, and gaps form between the panels as a result of, for example, wind loads or seismic loads exerted on the building structure. The single tongue-and-groove joint also allows water to migrate through the joint. Thus, the conventional joining sides of building panels are not sufficiently durable and water resistant over time.

Accordingly, it is desirable to provide lightweight, strong building panels or other building components that are highly thermally and acoustically insulative. It is further desirable to provide building components that can be easily and quickly joined together in a manner that forms the integral structural framework of the building, so as to provide the benefits of a post and beam frame at a much lower cost. It is also very desirable to provide a building component having all of the foregoing properties in addition to being resistant to water, fire, rot, and insects, ^' and also being easily handled and reasonably priced. To achieve these beneficial criteria across a wide range of applications, it is also highly desirable for a manufacturer to be able to readily and inexpensively make such building components for different building structures having different sizes and strength-to-weight ratios over a wide dynamic range. It is also desirable to provide joinery on the joining sides of a panel that will form a durable, self-tightening, and water resistant joint between building panels that are connected together.

Summary of the Invention

The present invention is directed toward a composite building component having an insulating core therein and integral joinery along at least one edge that is adapted to attach to joinery of an adjacent building component to provide a structural load-bearing member between and integral to the attached components. In a preferred embodiment of the invention, the building component is a lightweight, fire- resistant, thermally and acoustically insulative panel that has front and back face sheets positioned opposite each other, top and bottom joining sides intermediate the front and back face sheets at opposite ends of the face sheets, and left and right joining sides intermediate the front and back face sheets extending from the top joining side to the bottom joining side, such that the front and back, top and bottom, and left and right sides define an interior chamber that has an insulating core therein. At least one of the top and bottom or left and right joining sides has integral joinery adapted to be securely joined to an adjacent building component to form a structural member of a building, such as a post or beam, wherein the structural member is an integral part of the building component.

In one embodiment, the integral joinery is a tongue or a groove construction that is adapted to mate with a groove or a tongue, respectively, of an adjacent building component. In a preferred embodiment the integral joinery has a tongue-and-groove construction on the joining side with the tongue positioned immediately adjacent to the groove. The groove extends inward toward the interior chamber and the tongue extends outward away from the interior chamber and away from the groove. The adjacent tongue-and-groove are shaped and sized to mate with tongue-and-groove joinery of an adjacent building component to form a double tongue-and-groove joint therebetween.

The face sheets and joining sides of a preferred embodiment of the building panel are made of lightweight, strong, thermally and acoustically insulative cellular material, such as composite cellular cement with high-silica mineral material therein. The face sheets of the preferred embodiment are attached to the joining sides of the building panel to provide diaphragmatic bracing of the joining sides around the interior chamber, resulting in a stiff panel. The building panel also has shear-resisting through connectors spanning between the front and back face sheets to resist shear forces exerted on the panel and to minimize or eliminate shear forces exerted on the insulating core. The insulating core fills the interior chamber and supports the shear-resisting through connectors, and thus increases the compressive strength of the

total building panel, resulting in a very lightweight, stiff panel that is highly resistant to wind forces, seismic forces, and other forces.

A plurality of building panels of the present invention are interconnected to build a structure by mating the joining sides of adjacent panels together to form integral laminated structural members between the panels. The integral laminated structural members between the panels provide an integral post and beam frame that extends continuously along the entire height and length of a resulting building structure. A unique point of difference in this invention and common practice within the building component industry is the method of making the composite building component panel. The method of the present invention includes joining all but one of the front and back face sheets and joining sides of the building component together so as to define an interior 6-sided chamber with one side open. The interior chamber is filled through the open side with an insulating material, such as foam or the like, thereby forming the insulating core, and the one remaining side of the building component is secured in place after the interior chamber is sufficiently filled. An alternative method of making the building panel includes joining the joining sides and the front and back face sheets together to form the 6-sided interior chamber and injecting the insulating core into the interior chamber through one or more injection holes in the joining sides on the front and back face sheets. These methods of making the building component can be easily and closely controlled by a manufacturer to obtain the desired strength-to-weight ratio and the desired thermal and acoustical characteristics of the building component.

Brief Description of the Drawings Figure 1 is an isometric view of a building panel in accordance with the subject invention with a corner of the panel partially cut away showing an insulating core and a shear-resisting through connector.

Figure 2 is a schematic exploded view of the panel illustrated in

Figure 1. Figure 3 is an enlarged cross-sectional view taken substantially along line 3-3 of Figure 1.

Figure 4 is a schematic exploded view of an alternate embodiment of the subject invention with molded joining sides having integral tongue-and-groove joinery therein and a conduit extending through the panel. Figure 5 is an enlarged cross-sectional view of the building panel of

Figure 4 taken substantially along a horizontal plane through the middle of the panel.

Figure 6 is a partial isometric view of a plurality of interconnected building panels in accordance with the subject invention.

Figure 7 is an enlarged cross-sectional view taken substantially along line 7-7 of Figure 6 showing a double tongue-and-groove joint between adjacent building panels.

Figure 8 is an isometric view of an alternate embodiment of the building panel having two sides with integral joinery and two flat sides without integral joiner}'.

Detailed Description of the Invention A building panel 10 in accordance with the subject invention is illustrated in Figures 1 and 2. The building panel 10 includes two opposing stress skin sheets with a first stress skin sheet forming a front face sheet 12 and a second stress skin sheet forming a back face sheet 14, wherein the front and back face sheets are on opposite sides of the panel and separated by a top joining side 16 and a bottom joining side 18 that are intermediate and at opposite ends of the face sheets. A left joining side 20 and a right joining side 22 are also intermediate the face sheets 10 and 12 and extend between the top and bottom joining sides 16 and 18 at opposite edges of the face sheets, thereby forming a box-like panel having an interior chamber 24 and an insulating core 26 within the interior chamber. Accordingly, the building panel 10 is a load bearing insulated panel that greatly increases the thermal efficiency of a panelized building structure constructed with these panels.

Each of the top, bottom, left, and right joining sides, 16, 18, 20 and 22, respectively, of the preferred embodiment are shaped to fit between the face sheets 12 and 14 to form an integral tongue 28 that extends along the length of each joining side and a groove 30 positioned adjacent to the tongue. Thus, the tongue 28 and the adjacent groove 30 form integral tongue-and-groove joinery 32 along the edges of the building panel 10. The tongue-and-groove joinery 32 along opposite joining sides, for example, the top and bottom joining sides 16 and 18, intersect with the tongue-and-groove joinery 32 on each of the left and right joining sides 20 and 22. As such, the tongue and groove joinery 32 of the illustrated embodiment extends around the perimeter of the building panel 10 and is substantially parallel to the front and back face sheets 12 and 14.

Each of the joining sides 16, 18, 20 and 22 of the preferred embodiment has substantially the same cross-sectional shape. The following description of the tongue-and-groove joinery 32 of the left and right joining sides 20 and 22 also applies to the tongue-and-groove joinery of the top and bottom joining sides 16 and 18. As best seen in Figure 3, each of the left and right joining sides 20 and 22 includes a

molded member 33 with a substantially L-shaped cross section. The molded member 33 has a bottom leg 34 perpendicular to the front and back face sheets 12 and 14 and a top leg 36 integrally connected to the bottom leg 34 that extends outward away from the interior chamber 24 parallel to the face sheets. The molded member 33 of the right joining side 22 is positioned between the front and back face sheets 12 and 14 slightly inward from the edges of the face sheets, so the edge of the back face sheet 14 extends beyond the bottom leg 34. This arrangement forms the groove 30 in the right joining side 22, wherein an inside surface 38 of the back face sheet 14 forms an outer wall 40 of the groove, the bottom leg 34 forms a bottom wall 42 of the groove. and an inner side of the top leg 36 forms an inside wall 44 of the groove. As such, the groove 30 extends inward toward the interior chamber 24 and terminates at the bottom wall 42. The groove 30 is shaped and sized to receive a tongue of an adjacent building panel when two adjacent panels are joined together, as discussed in greater detail below. The outer side of the top leg 36 is adhered to an inside surface 46 of the front face sheet 12 and is positioned so the top leg extends outward past the edge of the front face sheet. This arrangement forms the tongue 28 on the right joining side 22 of the building panel 10. Accordingly, the tongue 28 is immediately adjacent to the groove 30 and extends outward away from the interior chamber 24 in a direction opposite the groove. The tongue 28 is shaped and sized to fit into a groove of the adjacent building panel when the panels are joined together.

In the preferred embodiment, the top leg 36 of the L-shaped molded member 33 is shaped so the inside wall 44 of the groove 30 slopes toward the front face sheet 12. The sloped inside wall 44 makes the tongue-and-groove joinery 32 easier to join with an adjacent building panel, because the inside wall provides a guiding surface that guides the joinery together even if the panels are not aligned in the same plane, such that the building panels will not bind or hang up during panel connection. In addition, the edge of the back face sheet 14 is slightly offset from the edge of the front face sheet 12. The extent of the offset defines the length of the tongue 28 and the depth of the groove 30 and allows the symmetry between the tongue and the groove to be controlled. A shorter tongue 28 and shallower groove 30 arrangement creates joinery that is easier and faster to secure to joinery of the adjacent panel, while being able to maintain a symmetrical joint between the adjacent panels. However, the respective sizes of the tongue 28 and groove 30 must be large enough to provide sufficient surface area contact between the joining sides of interconnected panels in order to create a structurally sound double tongue-and-groove joint integral to the connected panels.

The molded member 33 of the left joining side 20 has a similar cross- sectional shape as the molded member of the right joining side 22 discussed above, and it is rotated 180° relative to the right joining side, so the top leg 36 that forms the tongue 28 of the left joining side attaches to the back face sheet 14. Accordingly, the tongue 28 on the left side of the building panel 10 is opposite the groove 30 in the right side of the panel, and the groove 30 in the left side of the panel is opposite the tongue 28 on the right side of the panel. This arrangement of the tongue-and-groove joinery 32 on opposite sides of the building panel allows a right side of one panel to securely fit with the left side of a second panel in a double tongue-and-groove joint 76, shown in Figure 7 and discussed in greater detail below, wherein the interconnected joining sides of the building panels form a laminated, load bearing, structural member, such as a post, between the panels and integral to the panels.

As best seen in Figure 2, the top and bottom joining sides 16 and 18. shown with phantom lines illustrating edge portions of the front and back face sheets 12 and 14, have a similar configuration as the left and right joining sides 20 and 22. with the tongue 28 on the top side of the building panel 10 opposite the groove 30 in the bottom side of the panel. Thus, the top side of a first panel will securely fit with the bottom side of a second panel in a symmetrical, double, offset, tongue-and-groove joint to form a symmetrical, laminated, load bearing, structural member between the building panels and integral to the panels.

In the preferred embodiment, the tongue 28 and groove 30 on the top joining side 16 intersect with the tongue 28 and groove 30, respectively, on the left joining side 20 as a continuous tongue and a continuous groove along the top and left sides of the building panel. Similarly, a continuous tongue 28 and a continuous groove 30 extend along the bottom and right sides of the building panel. This arrangement results in the continuous groove 30 on the top and left sides of the building panel 10 intersecting with the continuous tongue 28 on the right and bottom sides, respectively, and the continuous tongue 28 on the top and left sides of the building panel intersecting with the continuous groove 30 on the right and bottom sides. respectively. Therefore, the symmetrical tongue-and-groove joinery 32 extends around the perimeter of the building panel 10.

The front and back face sheets 12 and 14 and the molded members 33 of the left, right, top, and bottom joining sides 16, 18, 20, and 22, respectively, are adhered together with a conventional adhesive, such as Dalbert epoxy or the like, to define the interior chamber 24 of the building panel 10. Substantial strength is achieved in the building panel 10, because the front and back face sheets 12 and 14 span between the molded members 33 and diaphragmatically brace the building panel. The increased

strength of the building panel 10 from the diaphragmatic bracing allows the molded members 33 of the joining sides and the face sheets 12 and 14 to be made from a lightweight, closed cell, insulative material while providing a structurally sound building panel 10. In the preferred embodiment, the front and back face sheets 12 and 14, and the top, bottom, left, and right joining sides 16, 18, 20, and 22, respectively, are made of a lightweight mineral compound, including but not limited to an improved cement composition such as that disclosed in U.S. Patent Application Serial No. 07/859,585 entitled "Improved Cement Composition and Material", filed March 27, 1992, by Grant Record, the disclosure of which is incorporated herein, in its entirety, by the foregoing reference thereto. The cement composition is created from cellular cement and a sufficient amount of high-silica material to substantially improve the thermal and acoustical insulating and fire-resistant properties of the composition while not detracting materially from its strength. The composite cellular cement is created to include a plurality of fluid pockets having substantially the same size and shape, wherein the fluid in the pockets is of a density less than that of the cement used in the composition. By adding the fluid pockets to the composition, the overall density and weight of the composition is decreased and the insulating and fire-resistant properties of the composition are enhanced. Other compounds that could be used to form the face sheets and joining sides include, for example, aerated cement-base compounds, non-cement base compounds, or other suitable material that demonstrates a desired strength-to-weight ratio.

The composite cellular concrete face sheets 12 and 14 and joining sides 16, 18, 20, and 22 of the preferred embodiment have a density in the range of 20 to 150 pounds per cubic foot, and a minimum insulative value of 0.5R per inch. Although the components of the preferred embodiment are within the density range and above the minimum insulation value, the density or insulative values can deviate from the preferred values without departing from the spirit and scope of this invention. The preferred composite cellular concrete material is also flame resistant and is impervious to very high heat, e.g., in excess of 2000°F. Thus, the building panel 10 is fire resistant and has lightweight insulative integral joinery that forms insulative, structural posts and beams of the panelized building structure when a plurality of building panels are interconnected. The result of the insulative structural posts and beams is an integral structural frame of a building that greatly reduces heat loss through the frame and greatly increases the thermal efficiency of the building.

As best seen in Figure 3, the joining sides 16, 18, 20, and 22 further include an integral joint liner member 48 made of, for example, fiberglass and resin or

the like, to significantly increase the strength of the components of the panel without significantly increasing the weight of the panel. It is preferred that the integral joint liner member 48 be incorporated into the composite cellular concrete material when the components are molded or otherwise formed to facilitate efficient production of the components and to achieve a smooth outer surface of the joining sides or other desirable outer surface. In an alternate embodiment, the front and back face sheets 12 and 14 have an integral face sheet liner member of the same or similar material as the joint liner members to increase the strength of the face sheets. In another embodiment, a composite cellular material is used that forms sufficiently strong components with smooth outer surfaces, so the front and back face sheets 12 and 14 do not have the face sheet liner members therein, and the joining sides 16, 18, 20, and 22 do not have the joint liner members therein.

As best seen in Figures 1, 2. and 3 the building panel 10 of the preferred embodiment also has a plurality of through connectors 50 attached to the inside surfaces of the front and back face sheets 12 and 14 to increase the shear strength of the panel. The through connectors 50 are shear resisting members, which extend through apertures 52 in the insulating core 26 and across the interior chamber 24. The through connectors 50 also provide increased resistance to compression forces exerted on the building panel 10. This increased resistance to shear and compression forces by the through connectors 50 combined with the increased strength of the panel from the diaphragmatic bracing by the face sheets 12 and 14, discussed above, results in a very strong and versatile building panel.

The through connectors 50 illustrated in the figures are cylinders that are adhered with a conventional adhesive or otherwise securely attached at predetermined positions between the front and back face sheets 12 and 14 and resist shear forces exerted on the building panel 10 between the face sheets when the panel is incorporated into a panelized building structure. Accordingly, the shear-resisting through connectors 50 allow highly insulative material, such as urethane foam, to be used for the insulating core 26 even though the core material has poor shear resistance. The through connectors 50 of the preferred embodiment are solid composite cellular concrete cylinders, although other material and/or geometric sections could be used. In an alternate embodiment, the through connectors 50 are integrally connected to the face sheets 12 and 14, rather than being adhered in the predetermined positions.

The through connectors 50 keep the face sheets 12 and 14 of the building panel 10 flat and very stiff, so the face sheets distribute wind loads, seismic loads, or other loads over the entire panel and avoid concentrated point loads on the building panel. The flat, stiff cellular concrete face sheets 12 and 14 also allow the

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building panel 10 to be made with a deeper or thinner section while utilizing the lighter weight and insulative material without diminishing the load bearing capabilities of the building panel. Although the preferred embodiment incorporates the through connectors 50, a building panel that does not include the through connectors across the interior chamber 24 can be used in a building structure that will not be subjected to large shear loads.

The insulating core 26 completely fills the interior chamber 24 and surrounds or encases the through connectors 50 to provide a solid central core within the building panel 10 that is resistant to compressive loads exerted on the building panel. In the preferred embodiment, the insulating core 26 is a modified polyurethane foam material having a thermal insulating value in the range of 8R to 9R per inch. The range of thermal insulative values of the insulating core 26 is a preferred range, although the insulating core can have a thermal insulating value that deviates from the preferred range without departing from the spirit and scope of the invention. The polyurethane foam core allows the insulative value, the weight, and the compressive strength of the insulating core to be controlled during the manufacturing of the building panel by changing the density of the foam within the interior chamber 24. For example, if the density of the modified polyurethane foam is increased, the compressive strength of the insulating core 26 and, therefore, the compressive strength and stiffness of the entire finished panel, is increased, as is the overall weight of the building panel 10. Although the preferred embodiment uses modified polyurethane foam for the insulating core 26, other insulative materials can be used. It is preferable, however, that a lightweight material is selected for the insulation core 26 so that the strength-to-weight ratio of the panel 10 can be maximized. In addition to controlling the properties of the building panel by varying the insulating core 26, the building panel of the preferred embodiment can also be easily manufactured to have a preselected compressive strength, shear strength, tensile strength, flexural strength, weight, insulation value, and acoustical characteristic by varying the thickness of the composite cellular cement in the face sheets 12 and 14 and joining sides 16, 18, 20, and 22, and by varying the number and position of the through connectors 80 within the panel. For example, a builder can identify to a panel manufacturer the particular size, weight, strength, thermal insulation and acoustical insulation characteristics needed for a building structure. The panel manufacturer will then be able to easily and quickly design an entire set of panels in accordance with the required specifications by controlling the material and density of the insulating core, the density, size, and thickness of each face sheet and joining side, and controlling the number, geometric section, pattern, and strength of the shear-resisting through

connectors. Once the panels are designed, the set of panels can be quickly manufactured, as discussed in greater detail below. Accordingly, the building panel has a tremendous design variability such that the characteristics of a building panel in accordance with the present invention can be easily controlled during manufacturing by adjusting one or more of the above properties. Therefore, the building panel 10 is extremely flexible in its application and design and can accommodate a wide dynamic range of structural, thermal, acoustical and other related properties of a panelized building structure.

In an alternate embodiment of the present invention, as best seen in Figure 4, the building panel 10 has a molded top joining side 54, bottom joining side 56, left joining side 58, and right joining side 60, each having the integral tongue-and-groove joinery 32 molded therein. The joining sides are adhered together with the left and right joining sides 58 and 60 sandwiched between the top and bottom joining sides 54 and 56. so the tongue-and-groove joinery 32 is continuous around the perimeter of the panel. As best seen in Figure 5, the front and back face sheets 12 and 14 are adhered to the left and right joining sides 58 and 60 so the edges of the face sheets are flush with a step portion 63 on the joining sides adjacent to either the tongue 28 or groove 30. Accordingly, the size and shape of the tongue 28 and the groove 30 are determined during the molding process, and the edges of the face sheets 12 and 14 and the step portion 63 do not define the relative sizes of the tongue 28 and the groove 30. The top, bottom, left, and right joining sides 54, 56, 58, and 60 of this alternate embodiment are preferably composite cellular cement components formed in a mold to obtain the desired size, shape, and configuration of the tongue-and-groove joinery 32. The alternate embodiment shown in Figure 4 also has a conduit 62 that extends through an aperture 64 in the insulating core 26, and through coaxially aligned apertures 66 in the top and bottom joining sides 54 and 56. The conduit 62 provides a protective passageway through the building panel 10 and is positioned to align with similar conduits in adjacent panels, so a protective interconnected passageway can extend through a plurality of interconnected building panels. The conduit 62 is illustrated as extending vertically through the insulating core 26, but could be positioned to extend through one of the joining sides parallel to the integral joinery. One of ordinary skill in the art will recognize that the conduit 62 could also be incorporated into a building panel to extend horizontally through the panel 10 between and through the left and right joining sides 58 and 60. The preferred conduit 62 is an elongated polyvinyl chloride plastic tube or the like that provides a nonconductive.

waterproof channel through which electrical wiring, plumbing, or the like can be installed.

The above-described embodiments of the building panel 10 are shown with the tongue-and-groove joinery 32 on all four sides of the panel. However, as best seen in Figure 8, another alternate embodiment of the building panel 10 has a flat bottom side 68 that intersects the tongue-and-groove joinery 32 of the right joining side 22, and a flat left side 70 that intersects the tongue-and-groove joinery 32 of the top joining side 16. The building panel 10 illustrated in Figure 8 is typically used as a corner panel, wherein the flat bottom side 68 is a bottom edge of a panelized structure that sits on a foundation, and the flat left side 70 is a corner edge of the panelized structure. The building panel 10 of the preferred embodiment can be constructed with greater or fewer flat sides than the alternate embodiment illustrated in Figure 8 as necessary for a desired panelized building structure. The building panel 10 can also be constructed with shapes other than the illustrated rectangular shape. For example, the building panel can be shaped as a triangle, pentagon, octagon, or other geometric shape, with one or more of the joining sides having the integral joinery.

The building panel 10 shown in Figures 1, 2, and 3 is manufactured by gluing or otherwise securing the top, bottom, left, and right joining sides 16, 18, 20, and 22 together to form a frame-like structure having open front and back sides. The back face sheet 14 is adhered to the frame-like structure to close out the back side of the panel. This results in a box-like panel with an open-side that exposes the interior chamber 24. A plurality of the through connectors 50 is secured to the back face sheet 14 in predetermined positions to give the building panel 10 a predetermined shear strength. After the through connectors 50 are secured in place, the modified polyurethane foam insulating material is added to the interior chamber 24, thereby forming the insulative core 26. After the foam has been added, the front face sheet 12 is secured in place on the front side of the frame-like structure opposite the back face sheet 14 to close the front side of the panel.

In the preferred embodiment, the modified polyurethane foam is pumped into the interior chamber 24 as a liquid and allowed to expand in volume as closed-cell gas pockets are generated within the liquid foam. These gas pockets increase the insulative characteristics of the foam core. In one method of making the building panel the polyurethane foam within the interior chamber 24 is allowed to fully expand and overflow out of the interior chamber, then solidify, and excess foam is trimmed away before adhering the front face sheet 12 in place. In the preferred method of making the building panel 10, however, a predetermined amount of foam is pumped into the interior chamber 24 and the front face sheet 12 is secured to the joining sides 16, 18, 20,

and 22 before the foam fully expands and fills the interior chamber. Accordingly, the front face sheet 12 blocks the foam from expanding beyond the volume of the interior chamber 24.

In an alternate method of making the building panel 10, the top, bottom. left, and right joining sides 16, 18, 20, and 22 are joined together, the front and back face sheets 12 and 14 are connected to the frame-like structure with the through connectors 50 secured in place between the face sheets. Then, a predetermined amount of modified polyurethane foam is injected into the interior chamber 24 through at least one injection hole. Thereafter, the injection hole is plugged to prevent the foam from expanding and flowing out of the injection holes.

This manufacturing method can result in substantial pressure being exerted on the front and back face sheets 12 and 14 and joining sides 16, 18, 20, and 22 as the polyurethane foam tries to fully expand. Once the polyurethane foam solidifies, however, the pressure from the foam expansion ceases. If a more dense insulating core 26 is desired and a larger amount of foam is pumped into the interior chamber 24. the front and back face sheets 12 and 14 and the joining sides 16, 18, 20, and 22 are structurally supported by a jig or the like that fits around the panel and supports the outside of the panel to protect the panel from expanding and separating under the pressure exerted by the expanding foam. Accordingly, the density, weight, insulative value, and compressive strength of the insulating core 26, and thus, the resulting manufactured building panel, is easily controlled by increasing or decreasing the amount of foam pumped into the interior chamber 24 before the front face sheet 12 is secured in place.

After the polyurethane foam solidifies and the building panel 10 is removed from the jig, the front and back face sheets 10 and 12 are impregnated with a polymer to provide a smooth and bondable outer surface. A covering material 72, best seen in Figure 3, may be attached to one or both of the front and back face sheets 12 and 14 and bonded to the bondable outer surface to provide an aesthetically pleasing cover on the panel. The covering material 72 of the preferred embodiment is a laminate covering, although vinyl, paint, wallpaper, or other material could be used. The building panel is cured and the resulting building panel is a highly thermally insulating, strong, and lightweight panel.

In an alternate construction method of the building panel 10. referred to as monolithic pouring, a box form is provided with an outside dimension corresponding to the width, height, and thickness of the desired building panel. The box form includes first and second generally planer sides that are spaced from one another by a distance corresponding to the desired thickness of the building panel. Support members, such as

first and second support rods (not shown) are positioned interior of the box form for supporting a pre-formed insulating core during preparation. The support members are generally oriented horizontally or vertically and positioned centrally in the box form. The insulating core is then positioned proximate to the support members to be supported in the box form generally centered between the first and second planer sides. The panel support liner material such as, for example, a fiberglass laminate, is positioned inside the box form proximate the first and second planer sides. The support liner material may also be included on one or more sides of the resulting building panel. The box form has female mold portions shaped and sized to mold the tongue-and-groove joinery on the joining sides of the building panel. After the box form is prepared and the insulating core and form liners are in place, the composite cellular cement material is poured into the box form around the insulating core, such that the joining sides and the front and back face sheets will be formed and integrally connected. The monolithically poured face sheets that are integrally connected to the joining side also provide the diaphragmatic bracing of the panel as discussed above, such that a strong panel can be poured using lightweight material.

In this alternate construction method, the insulating core has a plurality of apertures formed therein so the composite cellular cement flows through and fills the apertures to make the through connectors 50 that integrally connect to the front and back face sheets. The resulting building panel 10 is very stiff and able to withstand large loads exerted thereon, because of the resulting strength-to-weight ratio achieved by the composite cellular cement material in combination with the compression resistant foam insulating core, and shear resisting through connectors.

As best seen in Figure 6, a plurality of building panels 10 of the present invention fit together to form a panelized building structure 74 by interconnecting the tongue-and-groove joinery 32 of adjacent panels to form an integral, symmetrical, double, offset, tongue-and-groove joint 76 between the panels. As best seen in Figure 7, the tongue-and-groove joint 76 between adjacent building panels has the tongue 28 and groove 30 of a first panel 82 that is secured into the groove 30 and joint 28, respectively, of a second panel 84. The resulting symmetrical, double, offset, tongue-and-groove joint 76 is secured together with a conventional adhesive such as the Dalbert epoxy. The front face sheets 12 of the first and second panels 82 and 84 abut each other in flush engagement, as do the back face sheets 14 to form a flat wall surface across the building panels and across the panelized building structure 74. The double, offset, tongue-and-groove joint 76 is a self-tightening, symmetrical joint that tightens so as to not open and become unsightly and weak when virtually any live, dead, seismic, wind, thermal load, or any other load caused by the

movement of the earth, is exerted on the panelized structure 74. The symmetrical offset double tongue-and-groove joint 76 self-tightens when a force having a normal component is exerted on the building panel. When the force is applied to one side of the building panel, an equal and opposite reaction force on the opposite side of the building panel causes the joint to press against itself and tightened within the joint. The symmetrical, double, offset, tongue-and-groove joint 76 further has a tortuous path that acts as a moisture dam to block migration of water through the joint, and acts as a thermal break to prevent heat loss through the joint.

In the preferred embodiment, the offset of the front and back face sheets 12 and 14 are such that the depth of the groove 30 is slightly greater than the length of the tongue 28 that fits into the groove to create a relief area 86 within the joint 76. The relief area 86 gives the tongue-and-groove joint 76 increased flexibility and acts as a pressure equalization chamber that allows pressure built up between the panels to be equalized rather than concentrated in particular areas, and also inhibits water travel to the inside of the structure due to pressure differentials between the interior and exterior of the building structure. In an alternate embodiment, semi-flexible bonding membrane 88 is positioned between adjacent panels in the tongue-and-groove joint 76 to fill the relief area 86 and to resist shear loads, including seismic loads caused by movement of the earth, exerted between the panels at the joint. In another alternate embodiment not illustrated, a non-elastic or non-flexible membrane is positioned within the relief area to control load resistance or other structural characteristics as desired for different panelized structures.

As discussed above and as shown in Figure 6, adjacent building panels 10 are interconnected with a left joining side of a second building panel mating with a right joining side 22 of a first, laterally adjacent building panel to form a laminated vertical structural post 78 between the laterally adjacent panels. Similarly, top and bottom joining sides 16 and 18 of vertically adjacent building panels are interconnected to form a laminated horizontal structural beam 80 between the building panels. The tongue-and-groove joinery 32 of the building panels allows the plurality of panels to be joined together such that at least one continuous laminated post 78 extends along the entire height of the panelized building structure 74 and at least one continuous laminated beam 80 extends along the entire length of the panelized structure. As a result, the panelized building structure 74 is very strong, lightweight, and resistant to a whipping action at the top of the panelized building structure caused by, for example, wind loads exerted on the building structure.

In a preferred embodiment, each building panel 10 is five feet wide, eight feet tall, and six inches thick. The front and back face sheets 12 and 14 are stress skin sheets having a thickness of approximately 1/4" to 1/8". and the joining sides 16, 18, 20, and 22, with the integral tongue-and-groove joinery 32, are approximately three inches deep. When the plurality of building panels are joined together to form, for example, a panelized wall, the interconnected joining sides form a six inch by six inch laminated post at every five feet of linear wall surface, and a six inch by six inch laminated beam at every eight vertical feet of wall surface. Accordingly, as building panels are stacked to accommodate the multi-story building structure, the six inch by six inch laminated structural support members are formed naturally at each junction between adjacent building panels. The above dimensions are provided for illustrative purposes, and a building panel in accordance with the present invention can have different dimensions and ranges of dimensions without departing from the spirit and the scope of the invention. The resulting panelized building structure is a very strong and well-insulated structure that has integral load-bearing post and beam members that can be easily and quickly constructed in a very time efficient manner. The face sheets and joining sides can be sized as required for different types of panelized structures. For example, a heavy-duty building panel can have 10" thick face sheets and proportionately large joining sides, whereas light-duty building panels can have 1/8" thick face sheets and proportionately small joining sides. Thus, the building panel 10 of the present invention can be manufactured to accommodate a wide range of building conditions.

From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.