Building wall panel and method of making same

A building wall panel having an exterior facing formed from a glass fiber reinforced concrete bonded to a metal wall panel support frame formed from a plurality of vertical members having a plurality of flanges thereon by a layer of glass fiber reinforced concrete overlaying both a portion of the rear surface of the exterior facing and the flange abutting the exterior facing at intervals along the length of each vertical member. A method of forming the building wall panel involves spraying a first layer of slurry, formed from a mixture of concrete and chopped glass fiber strands, on a flat smooth surface between elongate members secured thereto and interconnected to form building wall panel mold. A metal wall panel support frame formed from a plurality of vertical members is placed over the first layer of slurry such that a flange disposed on each vertical member abuts the first layer of slurry. A second layer of slurry is sprayed over a portion of the flange on each vertical member and over a portion of the first layer of slurry. Both layers of slurry are cured and the completed building wall panel is removed from the surface and the mold.

FIELD OF INVENTION 
The present invention relates in general to the building wall panel art, 
and more particularly to the art of manufacturing and mounting on 
buildings, a wall panel having an exterior facing formed from a glass 
fiber reinforced concrete. 
BACKGROUND ART 
A long felt need in the building wall panel field has been a prefabricated 
wall panel having either a finished exterior facing adapted for use as an 
exterior load bearing or non-load bearing wall on commercial buildings, 
such as multistory apartments or the like, or a wall panel having both 
major surfaces finished and adapted for use as an interior load bearing 
wall or non-load bearing partition for such buildings. The fire codes for 
many commercial buildings prohibit the use of flame transmitting materials 
in the construction of exterior and interior wall panels, consequently any 
wall panel adapted for such use must be fabricated from non-flammable 
material to conform to these codes. In addition to having the above 
qualities, the ideal wall panel should be capable of being prefabricated 
as large multistory or multibay panels to minimize on-site construction 
time. This of necessity requires that the panels have sufficient strength 
such that they may span relatively large distances, typically twenty feet, 
without the need of expensive and heavy supporting structures attached to 
the buildings. 
A wall panel having finished surfaces on both sides is shown by Balduf, 
U.S. Pat. No. 2,241,338. Balduf discloses a structure having a facing of 
plasterboard or gypsum board secured to one side of a frame formed from a 
plurality of metal studs. A relatively thin layer of plaster overlays the 
plasterboard on both sides of the frame. The structure as disclosed by 
Baldulf is not well adapted to prefabrication since the plasterboard is 
attached to the metal frame after the metal frame is secured within a 
building. In addition, the thin layer of plaster overlaying the 
plasterboard is affixed to the plasterboard after the partition is placed 
within the structure, thereby requiring time consuming, onsite fabrication 
to produce the finished partition. The Balduf partition is also not well 
adapted for exposure to an external environment. The relatively thin layer 
of plaster is easily cracked when exposed to high tensil and twisting 
forces such as are encountered on the exterior surface of a building. When 
exposed to normal weather cycles, the layer of plaster may easily separate 
from the underlying plasterboard. 
Another wall panel, shown by Martin, U.S. Pat. No. 3,885,008, has an 
external molded panel bonded to a frame constructed from wood. The 
external molded panel is formed from a plastic compound and is bonded to 
the wooden frame by overlaying the entire back surface of the molded panel 
and the sides of the adjacent frame members with a layer of fiberglass 
reinforced plastic. This wall panel has inherent structural as well as 
durability limitations. For example, the attachment of a rigid plastic 
produces a wall panel with an external surface subject to cracking and 
separation from the underlying wooden frame when exposed to the tensil and 
twisting forces occurring in a multistory structure. In addition, the 
inherent structural weakness of the underlying wooden frame generally 
prohibits prefabricating such a wall panel into a single large multistory 
panel. Since the plastic exterior molded panel, the bonding compound 
securing the molded panel to the wooden frame, and the wooden frame 
itself, are all flammable materials, the panel as disclosed by Martin 
would not satisfy the fire codes for commercial structures. If the wooden 
frame of Martin were replaced by a metal frame, Martin would then have a 
problem of bonding the rigid external plastic molded panel to a frame 
having more flexure than the wooden frame. In such a situation, when the 
frame flexed, the bonding would likely break, resulting in the separation 
of the molded panel from the frame. In addition, the underlying metal 
frame generally would weigh more than the relatively thin molded panel 
thereby contributing to the cracking or breaking of the external molded 
panel. 
The present invention overcomes these problems of the prior art by 
providing a building wall panel having an exterior facing formed from a 
glass fiber reinforced concrete bonded to a metal frame, formed from a 
plurality of vertical members, at intervals along the length of the 
vertical members. The bonding is provided by a glass fiber reinforced 
concrete similar to that used in forming the exterior facing. The use of a 
glass fiber reinforced exterior facing provides a building wall panel 
which is particularly well adapted for exposure to an external environment 
since such a facing has wear characteristics similar to those of concrete. 
The use of the metal frame as the supporting structure for such an 
exterior facing provides a wall panel having high tensil strength and one 
which can span large distances without the need of expensive support 
members affixed to the structure. Bonding the exterior facing to the metal 
vertical members at intervals along the length of each member provides a 
building wall panel which is particularly well adapted for prefabrication. 
The building wall panel employs materials which are neither flammable nor 
exhibit flame transmitting characteristics and thus the wall panel of the 
present invention conforms to the fire codes required for commercial 
structures. If the building wall panel of the present invention conforms 
to the fire codes required for commercial structures. If the building wall 
panel of the present invention is to be used as an interior wall or 
partition, a layer of gypsum board, dry wall, or the like may be easily 
and quickly attached to one side of the frame, such as by the use of 
self-tapping screws or the like and covered with a plaster faced tape 
producing a prefabricated wall panel having both surfaces finished. In 
situations where required, a layer of insulation may be easily attached to 
the wall panel between adjacent vertical members prior to attaching the 
layer of gypsum board. 
DISCLOSURE OF THE INVENTION 
According to one aspect of the present invention, a building wall panel is 
provided comprising a generally rectangular metal support frame formed 
from a plurality of vertical members each having a plurality of flanges on 
at least one side thereof extending outwardly from the edges along the 
length of the member. A thin, exterior facing formed from glass fiber 
reinforced concrete is disposed across one side of the support frame and 
abuts a flange on each vertical member. A layer of glass fiber reinforced 
concrete overlays a portion of the rear surface of the exterior facing and 
the flange abutting the rear surface at intervals along the length of the 
vertical member, thereby bonding the exterior facing to the metal support 
frame. 
According to another aspect of the present invention, a method of forming a 
building wall panel having an external facing formed from glass fiber 
reinforced concrete is disclosed comprising the steps of: fabricating a 
metal support frame from a plurality of vertical members each having a 
plurality of flanges disposed on at least one side thereof extending 
outwardly from the edges along the length of the vertical member; 
constructing a generally rectangularly shaped building wall panel mold 
from a plurality of elongate and smooth sided members detachably secured 
to each other and removably secured to a flat, smooth surface; spraying a 
first layer of slurry formed from a mixture of concrete and randomly 
oriented chopped glass fiber strands on the surface within the elongate 
members forming the mold in a layer having a substantially uniform 
thickness; placing the metal support frame over the first layer of slurry 
such that a flange on each vertical member abuts the first layer of 
slurry; spraying a second layer of slurry over a portion of the first 
layer of slurry and the flange abutting the first layer along the length 
of each vertical member; curing both layers of slurry and removing the 
completed building wall panel from the surface and the building wall panel 
mold.

BEST MODE OF CARRYING OUT THE INVENTION 
In one embodiment of the present invention, as shown in FIGS. 1-4, the 
building wall panel, shown generally at 20, comprises a plurality of metal 
vertical members 22 interconnected to form a wall panel frame. A thin 
exterior facing 24 formed from a first layer of glass fiber reinforced 
concrete is disposed across one side of the wall panel support frame. A 
second layer of glass fiber reinforced concrete 25 overlays a portion of 
the rear surface of the exterior facing and a portion of each vertical 
member at intervals along the length of each of the vertical members 
thereby bonding the exterior facing to the frame. Referring particularly 
to FIG. 3, each metal vertical member 22 forming the wall panel frame is 
shown to have a plurality of flanges 26 thereon extending outwardly from 
the edges along the length of each member. The flanges 26 provide a lip or 
a return means and enable the exterior facing 24 to be bonded to the metal 
frame. Insulation 30, in the form of strips or the like, may overlay the 
rear surface of the exterior facing adjacent each vertical members 22 
thereby producing a building wall panel adapted for exterior or interior 
use. Panels of gypsum board, dry wall, or the like, shown at 32, may then 
overlay the insulation 30 and be secured to each vertical member 22, such 
as by the use of self tapping screws 34 (see FIG. 3) or the like covered 
with a layer of plaster backed tape 35 (see FIG. 10) to provide a wall 
panel having both surfaces finished. If desired, a conventional texturized 
material 36 may overlay the entire rear surface (see FIG. 10) of the wall 
panel. 
Referring now to the flow chart of FIG. 5, and the associated FIGS. 6-10, 
one method of forming a building wall panel in accordance with the present 
invention will next be described. 
The building wall panel mold, shown generally at 40, is constructed to the 
shape of the desired finished building wall panel. Each member of the wall 
panel mold 40 is detachably secured to the other members comprising the 
mold, and removably secured to a flat, smooth surface. The wall panel mold 
40 is constructed from elongate members having generally smooth sides and 
from any suitable material such as wood, metal, or the like. The size of 
the wall panel mold 40 depends upon the desired size of the finished wall 
panel 20. In general, the panel mold is slightly longer and slightly wider 
than the wall panel metal frame to enable the metal frame to be snugly 
inserted within the mold during fabrication of the wall panel, as will be 
discussed. The means for detachably securing the panel mold members to 
each other, and for removably securing the panel mold 40 to the smooth 
surface, such as nails, are old per se and are not part of the present 
invention. Although FIG. 6 shows a wall panel mold 40 having a generally 
rectangular shape, it will be understood that other building wall panel 
shapes and corresponding wall panel molds also may be used in the practice 
of the present invention. 
As shown in FIG. 6, a layer of bond breaker 42 is applied to the surface 
between the elongate members forming the building wall panel mold 40 and 
to the members forming the wall panel mold by means of a spray gun 44 or 
the like. The layer of bond breaker 42 facilitates removal of the 
completed building wall panel 20 from both the smooth surface and from the 
wall panel mold 40. The bond breaker as well as the spray gun are old per 
se. 
A building wall panel frame is next constructed from a plurality of metal 
vertical members 22. Each vertical member has a plurality of flanges 26 on 
at least one edge thereof extending outwardly from the edges of the member 
along the length thereof. The frame is constructed such that the flanges 
26 are arranged in a plane adapted to abut the rear surface of the 
exterior facing, and permit bonding the exterior facing 24 to the vertical 
members forming the frame. In the preferred embodiment, the plurality of 
vertical members 22 are typically metal studs having a width of four 
inches but it is to be understood that it is possible to use studs formed 
of other materials and widths without departing from the spirit and scope 
of the present invention. In the preferred embodiment, the vertical 
members 22 are typically the height of one building story (normally twelve 
feet) but other lengths may be used as desired. Vertical members 22 are 
rigidly secured to each other by welding or the like and are disposed 
adjacent each other typically on sixteen inch centers to facilitate 
securing standard sized interior gypsum boards or the like thereto. It is 
to be understood that depending upon the use of the wall panel, vertical 
members may be disposed adjacent each other at other than sixteen inch 
centers without departing from the scope of the present invention. 
A mixture of concrete is then prepared using cement, sand, and water. In 
the present preferred embodiment, one hundred pounds of cement is mixed 
with thirty pounds of sand and enough water, approximately forty pounds, 
to make a flowable mix. It is to be understood that the weight of sand in 
the concrete mix can be varied from near zero to a weight equal to that of 
the cement without departing from the spirit and scope of the present 
invention. The cement, sand, and water are mixed in a conventional 
concrete mixer (not shown) and pumpted to a sprayer 46 through a line 47 
(see FIG. 7). Compressed air is furnished to the sprayer through hose 48. 
A substantially continuous strand of alkali resistant glass fiber is also 
run to a conventional chopper mechanism (not illustrated) associated with 
the sprayer 46 from a roll or the like. The glass fiber is chopped into a 
plurality of short segments and mixed with the concrete in a known manner 
to form a slurry of concrete and chopped glass fiber strands. The 
percentage of chopped glass fiber in the slurry may be varied in the range 
of from two to six percent of the weight of the concrete as desired to 
meet the strength needs of the building wall panel. The length of the 
chopped glass fibers also may be varied, but it has found that a length of 
about one and one half inches is satisfactory for most uses. One type of 
glass fiber which has been found to be satisfactory is marketed under the 
name CEM-FIL alkali resistant glass fiber by CEM-FIL Corporation of 
Nashville, Tenn. The chopped glass fiber strands have a random orientation 
with respect to each other when they are mixed with concrete. 
A first layer of slurry 27 is then sprayed on the smooth surface within the 
wall panel mold 40. Although the thickness of the first layer of slurry 
may be varied, it has been found that a satisfactory building wall panel 
capable of spanning multiple stories may be formed with a thickness of as 
little as three-eights of one inch, it being understood that the thickness 
of the slurry may be increased to increase the strength of the building 
wall panel to meet the needs of a particular application. After the first 
layer of slurry 27 has been sprayed over the smooth surface, and before 
the layer has cured, it is compacted, as by use of a roller 50 or the 
like, to form a layer of slurry having a substantially uniform thickness. 
Referring now to FIG. 8, the building wall panel frame is next snugly 
placed within the panel mold 40 such that the flanges 26 on each vertical 
member abut the first layer of slurry 27. Before the first layer of slurry 
has cured, a second layer of slurry, shown at 28, is sprayed over portions 
of the first layer of slurry and portions of each flange 26 abutting the 
first layer of slurry, at intervals along the length of each vertical 
member. The second layer of slurry 28 has a thickness sufficient to 
completely cover a portion of the flange 26. It has been found that 
overlaying the flanges 26 with slurry portions having a width of as little 
as four to six inches at two foot intervals along the length of each 
member is sufficient to bond the first layer of slurry to the frame. 
After the second layer of slurry 28 has been applied over both a portion of 
the flanges 26 along each vertical member 26 and a portion of the first 
layer of slurry 27, the building wall panel 20 is allowed to cure in the 
wall panel mold 40 for a period of approximately twelve hours. After that 
time, the mold 40 is removed from the smooth surface, the plurality of 
smooth sided members forming the mold 40 are detached from each other and 
from the wall panel, and the building wall panel is allowed to cure for an 
additional seven days. During this time, the building wall panel is 
maintained in a moist environment such as by intermittenly spraying the 
wall panel with water or the like. It is to be understood that the curing 
times mentioned above are only approximate and may be varied somewhat 
without departing from the spirit and the scope of the present invention. 
If desired, a layer of insulation 30 in the form of bats or a roll or the 
like may be applied over the rear surface of the cured slurry 27 between 
adjacent vertical members 22 and secured thereto as by gluing a plurality 
of pins (not shown) to the back rear surface of the slurry and by securing 
the insulation thereto by fastener means such as snap-on nuts or the like. 
Application of the insulation 30 at the factory where the building wall 
panel 20 is fabricated eliminates the often difficult and time consuming 
task of applying insulation at the building site after insulation of the 
wall panel. 
With reference to FIGS. 3 and 4, completed building wall panels 20 are 
secured to the exterior or interior of a structure such as by use of 
rivets, bolts or other conventional fasteners applied at the top and 
bottom ends of the building wall panel. Adjacent wall panels may be 
secured to each other by means of rivets 50, bolts 51 or the like, 
extending through abutting elongate members 22. A layer of caulking 
compound 52 or the like is applied between adjacent wall panels 20 to seal 
the panel joints and prevent moisture from reaching the rivet 50. In 
situations where it is necessary to secure a plurality of building wall 
panels together to form an exterior wall having a finished interior 
surface (see FIG. 4), such as between adjacent floors in a multistory 
structure, the lower wall panel is first secured to the lower floor member 
such as by rivets. Bolts or the like. The upper floor member 58, typically 
having a plurality of metal flanges 56, 57 secured at each edge thereon is 
secured to the lower wall panel in a similar manner. The upper wall panel 
is then secured to the flanges 56, 57 and the lower wall panel. A trim 
piece 60 may then be added at the edge formed by the floor member 58 and 
upper wall panel. Other methods to secure a plurality of building wall 
panels to an adjacent floor may be used to practice the invention, such as 
by welding an angle member to the upper wall panel and providing the floor 
member 58 with a pocket to engage and secure the angle member. 
With reference to FIG. 10, if it is desired to provide a wall panel having 
both major surfaces finished, a panel 32 of gypsum board or dry wall or 
the like, may be applied to the surface to each vertical member 22 by 
means of a plurality of self tapping screws 34 or the like. If self 
tapping screws are used, a thin layer of plaster backed tape 35 is applied 
at the edges between adjacent sheets of gypsum board 32, as well as over 
each row of the self tapping screws to form a wall panel 20 having a 
finished exterior as well as interior surface. If desired, a final layer 
of interior facing material 36 such as a texturized plaster, paint or the 
like may be applied over the gypsum board 32 as by means of sprayer or the 
like. 
INDUSTRIAL APPLICABILITY 
The present invention has applicability in any situation where it is 
necessary to provide a structure with a prefabricated building wall panel 
adapted for exterior as well as interior use.