Construction panels for structural support systems

A construction panel is provided comprising a core of expanded or foamed polymeric material embodied between two major face members of resin reinforced with glass fibers. The side walls of the panel comprise pultrusion angle members which are encapsulated in the panel within the major face members. Elongated U-shaped pultrusion reinforcing members may be disposed within the panel to provide reinforcement and a channel for the receipt of wires, pipes, or to act as heating, air conditioning or vacuum cleaning ducts. The glass fibers used to reinforce the major face members are in multidirectional orientation and have portions extending into the interior of the panel to provide a mechanical and chemical bond between the core and the major face members. The pultrusion members may be made from resin reinforced with continuous strands of glass fibers in unidirectional orientation, and are preferably prestressed.

BACKGROUND OF THE INVENTION 
This invention relates to construction panels for structural support 
systems having high strength to weight ratios and excellent insulating 
properties. The construction panels may be used to build walls, floors, 
roofs, exterior fascia panels, facades, curtain walls, spandrels, balcony 
dividers, interior partitions, ceilings, etc. for industrial, commercial 
and residential buildings. 
Traditionally, buildings have been constructed from a wide variety of 
materials. Among the more common are wood, cinder block, brick, concrete, 
metal, and glass. Each has particular advantages and disadvantages. Wood, 
while relatively easy to work with, is quite flammable, requires the labor 
of skilled carpenters who take a long time in constructing an entire 
building, and is becoming increasingly expensive. Cinder block and brick 
are both quite heavy, resulting in high transportation costs and require 
the work of skilled masons over a long period of time to construct a 
building therefrom. Concrete is difficult to transport, fairly expensive 
and requires the use of special techniques and equipment, in order to 
produce a building therefrom. Metal panels are not good insulators and 
require the services of welders, riveters or other personnel to fasten the 
panels together and to the supporting structure by bolts, rivets or the 
like. Glass is breakable, hard to transport and is not a good insulator. 
Because of these disadvantages, new materials have been and are being 
developed to replace the traditional building materials. 
There is an increasing awareness that the world's natural resources must be 
conserved for future generations. The importance of adequately insulating 
buildings has been stressed by government and private industry alike. By 
properly insulating a building, consumers of energy used to heat and cool 
the building may save money, while at the same time aiding to conserve 
natural resources. In addition, by reducing energy demands to heat and 
cool our homes, offices, factories and the like, the citizens of the U.S. 
can help reduce our country's dependence on imported oil and natural gas. 
Various methods of insulating buildings have been proposed. Rolls of 
insulating material having various degrees of thicknesses may be purchased 
and unrolled at the job site adjacent the wall, floor, and roof members to 
be insulated. For pre-constructed structures, insulating material may be 
blown between the outer facing and the inner walls of a building to the 
desired density. 
Another technique of providing adequate insulation for buildings is to 
incorporate insulating material in prefabricated building panels. These 
panels offer the advantages of good insulating properties, mass 
production, and ease of on-site assembly of the panels, among others. 
These panels generally comprise a core of insulating material surrounded 
by structurally rigid panels. The core of insulating material may comprise 
balsa wood, glass wool, foamed or expanded polymeric materials such as 
polystyrene, polyvinyl chloride, polyurethane, etc. The core material may 
be surrounded by panel members comprising first and second major face 
members and side and end walls of such materials as plywood, metal, resin, 
and resin reinforced with fibrous glass rovings, etc. Generally, these 
panels are strong, lightweight and provide excellent insulating 
properties. 
These modular panels also have some disadvantages. Since the foam used in 
forming the core is not elastic, once it is compressed, a space develops 
between the core and facing member. This results in weakened structural 
integrity and may be responsible for such conditions as warping, buckling 
and cracking of the face member or of the entire panel. An additional 
advantage is that the major face members generally cannot withstand a 
great amount of load bearing pressure as may be encountered when the 
panels are used as part of a floor or, in some climates, a roof. To make 
the panels stronger, various reinforcing means have been incorporated 
within them. The following patents are representative of the way in which 
the prior art has attempted to overcome the problems and disadvantages 
associated with foamed core sandwich-type panels. 
Boyer, in U.S. Pat. No. 2,376,653, discloses a laminated panel comprising a 
thermoset resin containing reinforcing materials such as sisal, cocoanut 
shell fibers, wood excelsior, etc. bonded between two fibrous sheets. 
Spacers of wood or synthetic thermoset resin are placed between the inner 
surfaces of the spaced sheets to offset any tendency of the panel to 
buckle or warp. 
Shwayder, in U.S. Pat. No. 2,880,473, discloses a fibrous glass lamination 
comprising a core of hard rigid material, such as Masonite, kraft paper, 
heavy carboard, sheet steel, etc., encased within a thin skin of bibrous 
glass which acts to resist the tension of bending forces upon the 
laminate. Reinforcing bars or tubes may be located within the inner layer. 
Other embodiments show reinforcing bars extending from the inner surface 
of the fibrous glass coating out of the laminate. The reinforcing bars or 
tubes extending from the face of the laminate are parallel to each other 
so that one laminate may be interlocked with another laminate. 
Weinrott, in U.S. Pat. No. 3,462,897, discloses a panel structure 
comprising a frame made of wood to which are attached outer skins made of 
plywood or asbestos. Urethane foam is injected under pressure and heat 
into the cavities formed by the skins and the frame to form a core which 
adheres to all of the surfaces in contact therewith so that the resultant 
panel structure is a stressed skin structure. The panels may be used for 
walls, floors, or roofs and are particularly adapted for onsite assembly 
into a building. 
Andersen, in U.S. Pat. No. 3,573,144, discloses a sandwich-type structural 
panel wherein face sheets of woven glass cloths impregnated with an epoxy 
or polyester resin are bonded to a core. The core comprises a plurality of 
spacer blocks made of balsa wood or foamed polymeric material. The spacer 
blocks are connected to each other by undulating strips of resin 
impregnated fibrous webs, wherein the fiber is glass fiber or other 
natural or synthetic, organic or inorganic material. Reinforcing strips of 
the same type of resin impregnated fibrous material may be placed between 
adjacent spacer blocks to further strengthen the panel. 
Payne, in U.S. Pat. No. 3,733,232, discloses a composite building panel 
wherein a variety of base sheet materials, such as sheet steel, plaster 
board, asbestos felt or the like, may be combined with outer facing sheets 
of metal or other suitable material by means of a foamed or expanded 
plastic core. The facing sheet is preferably corrugated and the foamed 
plastic material may be foamed polyurethane. 
Allard, in U.S. Pat. No. 3,791,912, discloses a sandwich-type construction 
panel wherein reinforcing bars of metal are placed between a foam core and 
covering material comprising resin incorporated with glass fibers. The 
core or body is formed from an extruded block of foamed polymeric 
material, such as polyvinyl chloride or polyurethane. The core or body of 
foamed polymeric material has grooves cut into its surface according to 
the dimensions of the metal reinforcing bars, such as those used in 
reinforced concrete construction, but these are not prestressed. The resin 
coating includes flexible glass fibers disposed in several layers within 
the resin covering. The resin covering is applied to the core or body such 
that the metal reinforcing rods are between the core and the resin 
covering. Allard also discloses several other embodiments of building 
panels based on the concept of using metal reinforcing rods with foamed 
polymeric material sandwich-type structures. 
Watkins et al., in U.S. Pat. No. 3,898,115, disclose a sandwich-type 
building panel comprising a sheath of resin reinforced with glass fibers 
filled with a self-foaming polyurethane which forms the inner core. Voids 
may be left within the inner core to provide for channels for electrical 
wiring, water pipes or air conduits. In an alternate embodiment, the core 
is W-shaped. A plurality of triangular foam blocks are placed between two 
mats of woven glass fibers. The top mat is stitched to the bottom mat 
adjacent the base of each foam block and covers the apex of the foam 
blocks. Another layer of oppositely disposed triangular foam blocks are 
placed on top of the second layer immediately after the second mat has 
been sprayed or impregnated with a resin. A third mat of woven glass 
fibers is placed over the second layers of blocks and impregnated with 
resin. The entire core structure is then sandwiched between two sheets of 
resin impregnated with glass fibers. In either of the embodiments, the 
panels may be joined together along their coacting edges by means of a 
plurality of bolts, rivets or other fasteners through holes in flanges 
formed in the edges of the panels. 
Johnson, in U.S. Pat. No. 3,920,871, discloses a structural element 
particularly suitable for forming curved structures, such as boat hulls. 
The structural element comprises parallel rows of alternately oppositely 
undulated bundles of glass fiber rovings which are woven over and under 
adjacent parallel foamed plastic slats. The rovings are loosely woven so 
that there are spaces between the adjacent foamed plastic slats to allow 
for curvature of the structural element. Face sheets of woven glass fibers 
or other woven materials are placed on either side of the structure. A 
settable resin is then used to impregnate the woven structural elements so 
that all voids between the woven rovings, the woven face sheets and the 
foamed plastic slats are filled with the settable resin. The impregnation 
of the structural element with the settable resin produces upon setting 
"I-beams" of resin between the foamed plastic slats and provides a surface 
coating of resin which is integral with the "I-beams", to provide a 
strong, rigid, unitary structure. 
SUMMARY OF THE INVENTION 
The present invention overcomes the structural deficiencies of the prior 
art, including the defiencies associated with the above-described patents. 
The present invention provides for contruction panels for structural 
support systems comprising a core of extended polymeric material embodied 
between first and second major face members made of resin reinforced with 
glass fibers having increased load-bearing characteristics when compared 
with prior art panels. The resin used to make the major face members is 
reinforced with glass fibers in multidirectional orientation for 
multidirectional stability and strength. Some fibers extend into the 
interior of the panel so that a mechanical, as well as chemical bond is 
formed between the core and the major face members when the core is foamed 
in situ. 
The panels of the present invention have side walls comprising pultrusion 
angle members encapsulated within and/or bonded to the major face members. 
If necessary, one or a plurality of pultrusion reinforcing members are 
disposed within the panel between the major face members and bonded to the 
major face members. The pultrusion angle members forming the side walls of 
the panel and the pultrusion reinforcing members are made of resin 
reinforced with continuous strands of glass fibers in unidirectional 
orientation. The glass fiber strands are placed under tension as the resin 
cures to form prestressed pultrusion members. These prestressed pultrusion 
members provide the panels with increased structural strength, 
longitudinally and vertically. 
The pultrusion angle members which form the sides of the panel have a 
portion extending beyond the plane of one of the major face members of the 
panel to provide a flange for the interconnection of the panel members in 
abutting relationship by the use of fastening means to fasten the flanges 
together.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in detail, wherein like numerals indicate like 
elements, there is shown in FIG. 1 a floor or other load-bearing structure 
10 made of a plurality of panels 12 and 20 according to the present 
invention. Although load-bearing structure 10 is shown as a hexagonal 
structure, it could be rectangular, circular or any other desired shape, 
as could each of the individual panels. 
The term "load bearing" refers to panels and structures which generally 
have loads bearing on their major face members, that is, the panels or 
structures are generally placed so that major face members are horizontal. 
The term "non-load bearing" refers to panels and structures which 
generally support loads on their edges or sides, rather than on their 
major face members. 
Panel 12 is a left-hand triangular-shaped construction panel having angles 
of 30.degree., 60.degree. and 90.degree.. Panel 12 is conveniently 
denominated a left-hand panel since as shown in FIG. 1, panel 12 is to the 
left of panel 20. Right angle triangular panels 12 and 20 are 
substantially mirror images of one another and are fastened together in 
edge abutting relationship along the sides of the triangle between the 
right angle and the 30.degree. angle by means discussed below. 
The dimensions of the panels will depend upon the load design 
characteristics to which the panels will be subject in use. For example, 
the live load value for floors and, in some climates, roofs, is about 40 
pounds per square foot for residential buildings. The live load value for 
walls and some roofs in residential buildings is about 30 pounds per 
square foot. These values are compared with commercial and industrial 
structures having a live load value of about 55 pounds per square foot and 
a live load value of about 40 pounds per square foot. The load design 
strength of the panels can be engineered and adjusted by encapsulating 
within the panels reinforcing member 44 and 52, best seen in FIGS. 1 and 
4. 
The preferred lengths of the sides of the triangular panel are about 12 
feet, 21 feet and 24 feet when the panels are used for a floor. When the 
panels are used for a roof, because of the pitch required, the preferred 
lengths of the sides are 12 feet, 23 feet and 26 feet. The length of the 
sides of the rectangular panels are about 8 feet and 12 feet. Both the 
triangular panels and the rectangular panels can have a thickness of from 
about 2 and 5/16 inches to 5 and 5/16 inches, not including the depending 
flanges, depending on the thickness of the foamed core. The presently 
preferred thickness is about 3 and 5/16 inches, not including the 
depending flanges. The triangular panels may be truncated as indicated at 
14 in FIG. 1 to produce a central opening 16 for the running of pipes, 
electrical wires, heating and air conditioning ducts, telephone cables, 
antenna wires and the like. 
The internal structure of a panel used to bear heavy design loads will be 
described with particular reference to FIG. 4. Panel 20 comprises a first 
major face member 22 and a second major face member 24, both made of 
thermoplastic or thermoset resin reinforced with glass fibers. 
The particular type of resin used to make the major face members of the 
panels depends upon the environment and uses of the structure assembled 
from the panels. Thermoset resins become hard when heated. Thermoplastic 
resins become soft when heated and harden upon cooling. Among the suitable 
thermoplastic resins are the following: polystyrene, nylon, polycarbonate, 
styrene-acrylonitrile, acrylics, vinyls, acetals, polyethylene, 
fluorocarbons, polyphenylene oxide, polypropylene and polysulfone. Among 
these, the preferred thermoplastics are polyethylene and polypropylene. 
Suitable thermoset resins include polyesters, epoxies, phenolics, 
silicones, melamines and diallyl phthalate. Among the thermoset resins, 
polyesters and epoxies are preferred. 
Polyester resins are presently the most preferable for use with the present 
invention. Polyester resins are the polycondensation products of 
dicarboxylic acids, such as maleic, fumaric, phthalic and adipic acids, 
among others, with dihydroxy alcohols, such as ethylene, propylene, 
diethylene, and dipropylene glycols, among others. This resin is 
particularly preferred because of its ability, when catalyzed, to cure or 
harden at room temperature under little or no pressure. Unsaturated 
polyesters are usually crosslinked through their double bonds with a 
compatible monomer which also contains ethylenic unsaturation, such as 
styrene and diallyl phthlate, to become thermosetting. 
Various additives can be incorporated into the resin in addition to the 
glass fibers. Among these are pigments in almost any color, flame 
retardants, mold release agents and low shrink and low profile additives, 
usually thermoplastic resins added to the polyester to give low shrinkage 
and minimum surface waviness to eliminate or minimize the need for 
post-mold processing. 
The glass fibers are incorporated in multidirectional orientation in the 
resin used to make the major face members. By providing for a 
multidirectional fiber orientation, the major face members have 
essentially equal strength in all directions. Multidirectional fiber 
orientation is obtained by using chopped strands or mats woven from 
continuous or chopped strands. In the present invention, because of 
economy and ease of application, the use of chopped strands is preferred. 
The chopped strands are conveniently applied by spraying them onto a layer 
of resin which previously has been applied to a mold. 
When the fibers are in multidirectional orientation, the fibers can be 
incorporated within the resin up to about 50% by weight of the total 
resin-glass fiber composite. As used in the present specification and in 
the appended claims, the term "percent" refers to the weight percent based 
on the total weight of the resin-glass fiber composite. 
When the glass fibers are in multidirectional orientation, the resin-glass 
fiber composite may contain from about 10% to about 50% reinforcing glass 
fibers. The presently preferred percentage of reinforcing glass fibers is 
about 25%. With this amount of reinforcing fibers, a good balance is 
achieved between the required load bearing strength encountered in the 
construction industry and economy. The exact amounts of reinforcing fibers 
present in the resin-glass fiber composite used for the major face members 
of the panel depends on the particular resin used, the strength required 
and the expense of the materials. 
The chopped strands should be applied to the interior sides of the first 
and second major face members such that the strands extend from the 
surface of the resin-glass fiber composite into the panel as illustrated 
at 23 and 25 in FIG. 4, for a purpose to be described below. 
The panels used for the load bearing surfaces, such as the floor of a 
building, have side walls 26 and preferably include reinforcing members 44 
and 52. 
The side walls comprise F-shaped pultrusion angle members. Since both are 
substantially identical in structure, only one will be described. Each 
F-shaped pultrusion angle member comprises a portion 28 which extends 
below the plane of second major face member 24, a top horizontal flange 30 
and a bottom horizontal flange 32. Top flange 30 is preferably longer than 
bottom flange 32 because first major face member 22 generally supports 
more of a load than second major face member 24. Pultrusion angle member 
26 is encapsulated within the panel by having its top horizontal flange 
surrounded by and bonded to encapsulating portion 40 of the first major 
face member and having bottom horizontal flange 32 surrounded by and 
bonded to encapsulating portion 42 of the second major face member. By 
encapsulating the side walls in portions of the first and second major 
face members, an extremely strong structural panel may be obtained which 
resists separation of the major face members from the side walls. 
The side walls are referred to as "pultrusion" angle members because they 
are formed by a pultrusion process. The process of pultrusion is analogous 
to the process of extrusion. In extreusion, a plastic material is pushed 
through a die having a particular shape to form a product whose cross 
section has the shape if the die. In the process of pultrusion, and more 
particularly, continuous pultrusion, a plastic mass is pulled through a 
forming die to produce a pultrusion having a cross section corresponding 
to the shape of the die. There is no practical limit to the length of 
stock produced by continuous pultrusion, so long as the source of plastic 
material is continually replenished. 
The F-shaped pultrusion angle member forming the side walls of the 
embodiment of the present invention shown in FIG. 4 are formed by pulling 
a resin through an F-shaped die. The resin used for the pultrusion angle 
members may be the same as or different than the resins used in forming 
the first and second major faces of the panel, so long as the resin chosen 
for the pultrusion angle members is compatible with the resin chosen for 
the first and second major face members so that the encapsulation of the 
pultrusion angle members in the major face members is not inhibited. 
Polyester resins are the presently preferred resins for forming the 
pultrusion angle members. 
A major advantage of using pultrusion angle members to form the side walls 
as compared to side walls formed by other processes, is that the resins 
may be reinforced readily with continuous strands of glass fibers. 
Continuous strands of glass fiber roving are impregnated in a resin bath 
and are then pulled through an F-shaped die. A portion of the die may be 
heated to initiate the cure when using a thermoset resin. The cure may be 
completed by pulling the partially formed F-shaped pultrusion angle member 
through an oven. 
Preferably, the fibers of the continous strand or strands of glass fiber 
roving are in unidirectional orientation. This provides the greatest 
longitudinal strength in the direction of the fibers. Very high strengths 
are possible due to high fiber concentration and orientation parallel to 
the length of the stock being pulled through the die. By using a resin 
reinforced with continuous strand roving, a resin-glass fiber composite 
may contain up to 80% of reinforcing fibers if they are in unidirectional 
orientation. 
By subjecting the continuous strands to additional tension while the 
pultrusion angle members are being formed, the pultrusion angle members 
become prestressed. It is particularly preferable in the present invention 
to have the side walls of the panels formed from pultrusion angle members 
made from polyester resin reinforced with continuous strands of glass 
fibers in unidirectional orientation wherein the pultrusion angle members 
have been prestressed during formation. 
For large panels, especially those used for the load bearing structures, 
such as floors and in some instances, roofs, reinforcing members may be 
disposed between the two major face members within the panel. As shon in 
FIGS. 1 and 4, panel 20 contains two elongated reinforcing member 44 and 
52. Preferably, the elongated reinforcing members are U-shaped in cross 
section to form channel members 50 and 56 within the panel. Elongated 
reinforcing member 44 has horizontal flanges 46 and 48 integral with the 
uppermost portions of its side walls forming the U. Elongated U-shaped 
reinforcing member 52 likewise has horizontal flanges 54 (only one of 
which is shown in FIG. 4) integral with the upper portions of its side 
walls. The flanges help to distribute the weight supported by the panel 
and provide greater surface area for a stronger bond between the interior 
of first major face member 22 with the top portion of the flanges so as to 
allow reinforcing member 44 to be more strongly bonded within the panel. 
Reinforcing member 44 is disposed within the panel lengthwise for 
substantially the entire length of the panel, about in the middle, 
widthwise, of the panel. Reinforcing member 52 is disposed within the 
panel widthwise for substantially the entire width of the panel and may 
intersect reinforcing member 44 at any angle, but preferable at 
substantially 90. If desired, the walls of one of the reinforcing members 
may be eliminated at the point of intersection of the two members to 
provide an intersection passageway 55 between channels 50 and 56. The 
walls of channels 50 and 56 should be bonded together at intersection 
passageway 55. 
Channels 50 and 56 may contain electrical wires, water pipes, gas pipes, 
television and radio antenna cables, telephone wiring, alarm system 
wiring, etc. Alternatively, because the U-shaped elongated reinforcing 
members are bonded to the interior surfaces of major face members 22 and 
24, and to each other at intersection passageway 55, channels 50 and 56 
may be used for fluid conduits, such as heating ducts, air conditioning 
ducts, vacuum cleaning system passageways, or the like. When using 
channels 50 and 56 as conduits, there is no need to line them with any 
other materials. 
The reinforcing members may be made by the same process used to make the 
pultrusion angle members forming the side walls of the panel. Thus, it is 
proper to refer to reinforcing members 44 and 54 as pultrusion reinforcing 
members. They may be formed from polyester resin reinforced with 
continuous strands of glass fibers in unidirectional orientation for 
greater strength along their length. The number and placement of the 
reinforcing members within the panel is optional and may be determined on 
the basis of strength and cost factors. The thickness and shape of the 
reinforcing members obviously determine their strength and their cost. 
End walls 27 of triangular panel 20 and end walls 67 of rectangular panel 
60 may be either pultrusion angle members similar or identical in 
structure to side walls 26 and 66. Alternatively, and preferably for most 
cases, end walls 27 and 67 comprise a resin-glass fiber composite wherein 
the glass fibers are in multidirectional orientation similar or identical 
to the composite used to form the first and second major face members of 
the panels. Holes aligned with channels 50 and 56 may be cut into the side 
walls or the end walls of the panels to provide access to the channels. In 
some instances, it will be unnecessary to form end walls for the panels, 
such as truncated portion 14 of triangular panel 20. 
An insulating core is formed within the panel by causing an insulating 
material 58 to fill completely the interior of the panel, except in the 
channels formed within the reinforcing members, if any are present. 
The insulation is preferably an expanded or foamed polymeric material. 
Suitable polymeric materials include foamed polyethylene, foamed 
polypropylene, foamed polystyrene, foamed epoxy resins, foamed cellulose 
acetate resins, foamed phenolic resins, foamed ABS resins and other foamed 
polymers. The foamed core should have a density of at least 4 pounds per 
cubic foot so as to resist being compressed, and thus be highly resistant 
to delamination. A density of 4 pounds per cubic foot has been found to 
produce the optimal combination of thermal and mechanical properties. The 
density of the foamed core may be determined for the maximum load bearing 
requirements, thermal and sound insulating characteristics and cost for a 
particular structure. The preferred thickness of the foamed core is 
between about 3 to 5 inches, with 3 inches being the presently preferred 
thickness. 
Expanded or foamed polyurethane is particularly preferred. The polyurethane 
is preferably foamed in situ within the pannel. A polyol, such as 
polypropylene glycol is treated with a diisocyanate in the presence of 
some water and a catalyst, such as amines, tin soaps, or organic tin 
compounds. As the polymer forms, the water reacts with the isocyanate 
groups to cause cross linking and also produces carbon dioxide which 
causes foaming. Alternatively, trifluoromethane or a similar volatile 
material may be used as a blowing agent. The foaming is conducted within 
the panel under pressure so that the polyurethane foam fills the entire 
interior of the panel except for the channels. If the polyurethane foaming 
reaction is begun before the polyester resin completely cures, some cross 
linking may occur to create a chemical bond between the polyurethane and 
the polyester resin on the interior of the major face members of the 
panel. An uncured polyester resin may be placed on the interior surfaces 
of the pultrusion angle members and the pultrusion reinforcing members to 
create this chemical bond. 
As best shown in FIG. 4, the polyurethane also forms a mechanical bond with 
glass fibers 23 and 25 extending from the interior surfaces of major face 
members 22 and 24. The final coating of resin and glass fibers on the 
interior of major face members 22 and 24 is deliberately left unrolled so 
that glass fibers 23 and 25 may combine with the polyurethane foam to 
create a stronger bond without the use of any glue or other adhesive. The 
combined mechanical and chemical bonds provide a laminated panel having a 
synergistic strength greater than the combined stength and rigidity of the 
individual components. 
Building panels 20 may be joined together along their coacting side walls 
to form a common unitary structure such as a floor or roof. Preferably, 
adhesive such as polyester resin is coated on the side walls before they 
are fastened together. They may be fastened together mechanically by means 
of a plurality of bolts 36 and nuts 38 which extend through holes 34 in 
side wall portion 28 extending below the plane of the second major face 
member. The panels may be bonded to wall structures, foundations, 
ceilings, etc. by means of an adhesive such as polyester resin and 
suitable mechanical fastening means, if desired. 
Panels used in forming walls and other non-load bearing structures need 
not, and preferably do not contain pultrusion reinforcing members. The 
building panels used for these structures may be any shape. For the 
purposes of illustration and explanation, a rectangular panel 60 will be 
described. 
Rectangular panel 60 may be made of the same materials as triangular panel 
20. Therefore, a detailed description of the various components will not 
be given in relation to panel 60. Panel 60 comprises a first and second 
major face members 62 and 64 made of a resin-glass fiber composite having 
glass fibers 63 and 65 extending into the interior of the panel. The glass 
fibers used to reinforce facing members 62 and 64 are in multidirectional 
orientation. L-shaped pultrusion angle members 66 form the side walls of 
panel 60. F-shaped fultrusion angle members may be used when greater 
strength is desired. Each pultrusion angle member 66 has a top horizontal 
flange 70 and a portion 68 extending below the plane of the second major 
face member. Each pultrusion angle member 66 is encapsulated within the 
panel by being encapsulated within first major face member 62 by 
encapsulating portion 78 and bonded to or encapsulated within second 
facing member 64 by encapsulating portion 80. Insulating material 82, 
preferably polyurethane foam, is disposed within the interior of the panel 
and is bonded to major face members 62 and 64 by a chemical and mechanical 
bond. 
Non-load bearing panels 60 are joined together along coacting side walls by 
means of an adhesive such as polyester resin and mechanical means, such as 
bolt 74 which extends through adjacent aligned holes 72 in adjacent lower 
portions of pultrusion angle members forming the side walls of the panels. 
A nut 76 is secured to each bolt 74. 
The preferred process for forming the panels will now be described. 
A female mold made of wood, metal, resin reinforced with glass fibers, or 
the like, is coated with any conventional release agent compatible with 
the mold and the resin chosen for the panel. A gel coat of resin is then 
spread onto the release coating. Glass fibers in multidirectional 
orientation are distributed onto the gel coat, preferably by spraying, but 
other methods, including hand lay-up of continuous and chopped strand mats 
may be employed. The glass fibers may be rolled into the resin so as to be 
completely surrounded by the resin. These steps are repeated until a first 
major face member of desired thickness is formed. In the last application, 
the glass fibers are left unrolled so as to be able to extend into the 
interior of the panel. 
Previously prepared pultrusion angle members and, if desired, pultrusion 
reinforcing members are then placed within the mold and encapsulated 
within the resin-glass fiber composite before the composite has cured. The 
first major face member with the encapsulated side walls and bonded 
pultrusion reinforcing members is then allowed to at least partially cure. 
Simultaneously with the formation of the first major face member, a male 
mold is similarly coated with a release agent and several layers of resin 
and glass fibers to the desired thickness and allowed at least partially 
cure. Then either mold is inverted and mated onto the other mold so that 
the pultrusion angle members are encapsulated within the second major face 
member and pultrusion reinforcing member, if any, is bonded to the second 
major face member If desired, end walls may be formed either of pultrusion 
angle members or of resin-glass fiber composite. The end walls may be 
formed at the same time that the first major face member is formed or when 
the pultrusion angle members are encapsulated within the first major face 
member. The end walls are bonded to the side walls and to the first and 
second major face member. 
Before the final end wall is completely formed, liquid polyurethane is 
introduecd into the interior portions of the panel and allowed to expand 
or foam, preferably under pressure, so that the insulation completely 
fills the interior of the panel. As pointed out above, by foaming the 
polymeric material before the resin of the first and second major face 
members is completely cured, a mechanical and chemical bond is formed 
between the foam core and the face members. After the foaming process is 
complete and the resin-glass fiber composite is completely cured, the 
panel is removed from the molds and a plurality of holes are drilled in 
the portions of the side walls extending below the plane of the second 
major face member. Of course, during the formation process, openings for 
windows, doors, archways and the like will be provided in the panels where 
desired. 
The panels may be treated for aesthetics as desired. Various exterior 
aesthetic treatments include siding, paneling, shingling, providing a 
stone or masonry facade, etc. The attachement of these architectural 
elements is very easy due to the fact that the resin-glass fiber composite 
can withstand the forces of nailing, riveting, etc. without cracking. The 
resin-glass fiver composite is also self-trapping. Traditional interior 
architectural elements include hardwood floors, tile, carpets, wallpaper, 
paneling, acoustical ceiling tiles, etc. Alternatively, the panels may be 
utilized as they come finished from the molds where the desired pigments 
and low profile additives have been incorporated in the resin-glass fiber 
composite. 
The building panels according to the present invention have the following 
advantageous characteristics: moderate cost, high strength to weight 
ratio, excellent dimensional structural stability, excellent thermal 
properties, excellent sound insulation properties, good fire retardancy, 
good dielectric properties, excellent resistance to hydrostatic pressures 
and capillary moisture absorption, excellent resistance to chemicals and 
alkalis, and excellent resistance to abrasion, scratching and impact. 
By using the panels according to the present invention in building 
structures, the following typical and frequently costly elements of 
structures may become obsolete: termite, rodent and other pest control; 
rot-proofing treating; damp-proofing and waterproofing treatments; floor 
joists, bridging and other typical underlayments; exterior wood framing; 
ceiling and roof rafters; wall and roof sheathing and necessary flashings, 
separate insulation precesses; plasterboard or drywall for lining the 
inside of the walls and ceiling of the building; and duct work for 
heating, cooling and the like. In addition, the amount of nails and other 
fasteners presently used in framing, rafters, etc. may be reduced, as may 
the amount of lumber required in present structures. 
The present invention may be embodied in other specific forms without 
departing from the spirit or essential attributes thereof and, 
accordingly, reference should be made to the appended claims, rather than 
to the foregoing specification as indicating the scope of the invention.