Interlocking roof panels with built in pitch

Modular roof panels having sloped top surfaces and flat bottom surfaces are interlocked in edge-to-edge relation to one another to form a monolithic roof where the roof is pitched to provide moisture run off but where the space covered by the roof has a ceiling that is not pitched. Thus, the side walls of the structure have a common height. In a first embodiment, the top and bottom surfaces of the panels are covered with a skin, and in a second embodiment only the top surface is so covered. The first embodiment is used in original roof construction and the second is used in roofover construction. In both embodiments, the core material is preferably expanded polystyrene and the skin is preferably metallic. The skins are bent to interlock contiguous panels.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates, generally, to building construction. More 
particularly, it relates to a modular roof panel construction where the 
slope of the roof is built into the panel. 
2. Description of the Prior Art 
Expanded polystyrene (EPS) is used extensively in the construction industry 
because it is light in weight yet strong and inexpensive. For example, its 
closest competitor, urethane foam, costs about three times as much. 
EPS is also desirable because it can be cut into different shapes with some 
ease. Architects often specify its use when placing decorative columns or 
other designs on the facade of a building. More commonly, however, it is 
used in roof construction or as a supplemental roof known as a roofover. 
Since EPS is quite brittle, however, it is covered with a thin metallic 
skin if it is being used not as a decoration but as a working part of a 
structure. A suitable adhesive is employed to bond the skin to the EPS 
core. 
In the roofing industry, EPS panels are often used to overlie existing 
roofs to enhance the insulation of the space below the roof and to seal 
the roof against leakage. Typically, EPS roofing panels are of modular 
construction so that a plurality of panels may be combined to form a 
monolithic roof. Numerous patents have been awarded on interlocking means 
that facilitate the quick and easy joinder of individual panels, that 
prevent leakage of moisture through the seams, and so on. 
All of the EPS roofing panels of the prior art share a common feature: 
uniform thickness. Regardless of the size of the panel, the type of 
interlocking means employed, whether a metal skin is used on one or two 
sides thereof, etc., the thickness of the panel is always uniform along 
the extent and breadth thereof. 
Thus, all EPS roof panels heretofore known cause the same problems in the 
roof construction industry that are caused by the other materials used in 
the industry. To properly slope a roof, either a truss or other support 
surface having the desired slope must be built to support the roof atop 
walls having a common height, or the walls of the structure must be built 
to accommodate the slope. 
When the latter technique is employed, no two of the wall sections will 
have the same configuration. More particularly, each wall section will 
have a slope built into its top edge, and that slope must match the slope 
of the contiguous wall sections. 
Thus, the ceiling of the structure being provided with such a roof will be 
lower at its outermost edge than at its innermost edge, i.e., the downward 
slope of the roof translates into a downward slope of the interior ceiling 
of the space being roofed. Thus, the occupants of the space lose headroom 
as they approach the outer wall of the structure. 
Moreover, a structure with such a roof is less appealing aesthetically than 
is a structure where the end walls have a common height. 
If an EPS roof panel construction could be discovered that would enable add 
on rooms, for example, to have pitched roofs but unpitched ceilings, such 
a panel would revolutionize the construction industry. 
No EPS roof panel construction of the prior art teaches or suggests how 
such a leap in construction industry technology could be accomplished. 
In the urethane panel construction industry, U.S. Pat. No. 3,792,141 to 
Offutt shows what is called a "roof structure" that has a built in pitched 
roof and a flat bottom; however, it is well known in the urethane industry 
that urethane foam expands with enormous force as it cures, and that, 
consequently, large masses are required to mold urethane items of large 
sizes. Thus, the construction of a urethane panel large enough to form a 
part of a modular roof is not believed to be within the realm of 
practicality. Perhaps even more importantly, the Offutt construction 
teaches away from modular panels having edge-to-edge interlocking means. 
When the prior art is viewed as a whole and in its entirety, the vast scope 
and content of such art suggests, at most, continued evolutionary change; 
a breakthrough-type development in this art would not have been obvious to 
one of ordinary skill in this art at the time this invention was made. 
SUMMARY OF THE INVENTION 
The very longstanding but heretofore unfulfilled need for an EPS roof panel 
construction that obviates the need to slope roofs and ceilings at a 
common pitch is now fulfilled by interlocking EPS panels having flat 
bottoms and pitched tops. 
In a first illustrative embodiment, the top and bottom surfaces of the 
panels are covered with a metallic skin; in a second illustrative 
embodiment, only the top surface is so covered. Both embodiments include 
the use of cores of non-EPS construction. 
The first embodiment has utility in those constructions where the EPS 
panels are employed as the primary roofing material; the second embodiment 
has utility where EPS panels are placed over an existing roof to enhance 
its insulation or for other reasons. 
In both embodiments, a side elevational view of the panels shows a flat 
bottom and a sloping top, i.e., the top and bottom of the panel are 
oblique with respect to one another; the angle of the top surface 
determines the pitch of the roof. Thus, a space covered by either 
embodiment--even though only the first embodiment would be employed in 
original construction--would have a flat ceiling. Thus, the side walls of 
the structure will have a common height, thereby obviating the need for a 
truss or to custom build the supporting walls as required when roof panels 
of uniform thickness are employed. In new construction, accordingly, the 
add on look will be avoided and the appearance of a conventionally built 
roof will be provided. 
The second embodiment also includes novel means for securing the panels to 
the existing roof. Importantly, said novel means is not visible when the 
roof has been completed. Just as importantly, the novel means eliminates 
the need for throughbores through the panels. 
The primary object of this invention is to make obsolete the uniform 
thickness EPS roof panels of the prior art. 
A closely related object is to make obsolete add on structures having 
sloped interior ceilings. 
A general object is to advance the arts of original roof construction and 
roofover construction in a pioneering fashion. 
A more specific object is to provide invisible hold down means for roofover 
panels. 
These and many other important objects, features and advantages of the 
invention will become apparent as this description proceeds. 
The invention accordingly comprises the features of construction, 
combination of elements and arrangement of parts that will be exemplified 
in the construction hereinafter set forth, and the scope of the invention 
will be indicated in the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIG. 1, it will there be seen that an add on room or 
other structure made in accordance with the techniques of the prior art is 
denoted 10, generally. It is critical to note that the EPS roof panels 12 
that have been employed to construct the roof have a common thickness. 
Moreover, note that inner wall 14 has a height greater than central 
support post 16, and central support post 16 has a height greater than 
outer wall 18. It follows that the wall sections lying in the plane of the 
paper have different contours because their respective upper edges must 
match the slope of the roof 12; accordingly, an installation of this type 
requires custom making of the support posts, the outer wall, and the side 
walls, i.e., the walls in the plane of the paper. Just as importantly, the 
occupants of space 20 have less headroom when standing near outer wall 18 
than when standing near inner wall 14. Furthermore, the aesthetic 
appearance of the structure 10 is nominal, i.e., the structure 10 has an 
unpleasant added-on look. 
Referring now to FIG. 2, it will there be seen that an embodiment of the 
invention that illustrates a preferred expression thereof is denoted as a 
whole by the reference numeral 30. Walls and support posts 14, 16, and 18 
maintain their designations from FIG. 1, but it should be observed that 
support post 16 and outer wall 18 are now of the same height as inner wall 
14, and that, accordingly, the wall sections in the plane of the paper 
have a common configuration. Specifically, the building construction of 
FIG. 2 includes a plurality of roof panels disposed in edge-to-edge 
relation with one another, in combination with a plurality of wall panels 
of uniform height disposed in edge-to-edge relation with one another. 
Thus, the space denoted 20 has a common head room throughout. This is 
achieved by the provision of the novel panels 32, only one of which can be 
seen in this side elevational view, that are employed to provide the roof 
for structure 30. Note that the top 34 of each panel 32 is sloped to 
provide the needed pitch, and that the bottom 36 of the panels is not 
sloped; thus, occupants of space 20 see a ceiling having a uniform height 
and external observers of the structure 30 see an aesthetically pleasing 
room having the appearance of an original construction. 
The taper of roof 30 is adjustable so that any pitch can be provided. 
Significantly, the oblique relationship of top surface 34 and bottom 
surface 36 was heretofore unknown in the EPS roof construction industry. 
It should of course be understood that the novel roof is made from a 
plurality of panels 32 that are interlocked with one another along their 
abutting edges. In FIG. 2, an edge of panel 32 is denoted 38. EPS panels, 
typically, have a breadth of about four feet; thus, where an add on room 
is twenty feet in length, five panels 32 disposed in edge-to-edge relation 
would be required to provide the needed roof. Where the add on room is 
sixteen feet in width, i.e., where the distance between inner wall 14 and 
outer wall 18 is sixteen feet, then each panel 32 would be sixteen feet in 
length. Clearly, depending upon the width of the room and the desired 
pitch of the roof, the difference in thickness of the panels at their 
innermost ends 40 and their outermost ends 42 will vary, i.e., the amount 
of taper of panels 32 will vary. 
A pair of contiguous panel 32 edges are shown in FIG. 3. The foam core 44 
of a first edge is unsculpted as at 46, and the foam core 44 of a second 
edge has sculpted therein a pair of square channel groove members, 
collectively denoted 48. Edges 50 and 46 thus abut one another when the 
panels are interlocked with one another. Each foam core is covered with a 
metallic skin 52 that is bonded thereto to protect it. The skin that 
protects the panel having the unsculpted panel edge 46 is bent at said 
edge into the form of an outwardly projecting "J"-shaped hook 54. Each 
hook 54 is accommodated within its associated groove 48 when the panels 
are interengaged to one another, and each hook engages a complementally 
formed inwardly projecting "J"-shaped hook 56 that is positioned within 
said grooves 48. 
FIG. 4 shows the panels of FIG. 3 when so interengaged. The gap between 
edges 46 and 50 does not appear in the commercial embodiment of the 
invention and is depicted merely to better explain the structure of the 
inventive panels. 
FIG. 5 shows panels 32 without their respective cores 44 so that only skins 
52 remain; this Fig. is provided so that the "J"-shaped hooks 54 and 56 
can be better seen. 
FIG. 6 shows how said hooks 54 and 56 are brought into interlocking 
relation to one another; the drawing shows how the panel including hooks 
54 is initially tilted with respect to the panel having hooks 56, and 
directional arrow 58 shows how the tilted panel is rotated to complete the 
interlocking procedure. 
FIG. 7 shows cabana panels 32, 32 in perspective. 
FIGS. 8-12 disclose the second embodiment of the invention. 
As shown in FIG. 8, there is only one skin 52 in this embodiment, i.e., the 
bottom surface 45 of core 44 is uncovered. This embodiment is employed as 
a roofover to overlie existing roofs made of tar and gravel. Thus, only 
the top surface of core 44 is covered with a skin 52; the uncovered bottom 
surface 45, being yieldable, thus conforms to the bumps formed on the 
existing roof and provides a tight seal thereagainst. Note that the top 
and only skin 52 of each panel is provided with the "J"-shaped hooks 54 
and 56 as in the first embodiment. 
In this embodiment, advantageous use is made of the square channel 48 that 
accommodates hook 56. A first part of a two part bracket is positioned 
within said channel to facilitate engagement of each panel to the 
pre-existing roof. In FIG. 8, the two parts of each bracket 60 are denoted 
62 and 64, but the construction of each bracket 60 is perhaps best 
understood in connection with FIG. 9. 
Part 62 is "L"-shaped; it includes base 66 that is apertured to receive 
therethrough a pair of screws 68 that are employed to secure part 62 to 
the roof of the structure. It further includes upstanding part 70. 
Part 64 has a compound shape as shown; it includes a square "U"-shaped part 
72 that overlies and lines the square-shaped channel 48, and a straight 
part 74 that overlies that part of edge 50 just below said channel 48. The 
uppermost end of upstanding part 70 overlies straight part 74 of part 64 
and a bore is formed through both of said parts to accommodate screw 76 
that joins said parts together and to foam 44 of the panel. Parts 62 and 
64 could be provided as a single piece, but the use of two parts provides 
the feature of adjustability. 
FIGS. 10 and 11 provide an animation showing how the panels are 
interlocked, with FIG. 10 showing the initial angular tilt and the 
rotation, indicated by directional arrow 80, required to achieve the 
interlocked position of FIG. 11. Note how the yieldability of the foam 
core allows it to conform to the head of the screws 68 and 76. Note also 
that bracket 60 is completely hidden from view when the novel panels are 
interlocked. However, this invention also contemplates that the panels 
could be held down with conventional throughbore attachments. 
FIG. 12 shows how these novel panels of the second embodiment can be 
employed as a roofover to a tar and gravel roof that is pitched in two 
opposite directions. The panels are secured to the roof by novel brackets 
60, and a flashing 90 that bridges the gap between the panels at the apex 
92 of the roof is then secured to opposing panels by suitable attachment 
means such as screws 94. The gap at the bottom of each panel, i.e., 
between panel bottom wall 45 and the surface 94 of the roof, does not 
exist, but is shown merely to distinguish the roof from the panels. 
In all embodiments, the roof panels are interlocked with one another at 
their respective mating edges and are positioned atop the wall panels to 
form a room having a roof with a flat bottom surface and a sloped top 
surface having a predetermined pitch. Thus, a room covered by the novel 
roof includes a plurality of side walls of uniform height. 
This invention is not limited to the specific interlocking means shown; 
numerous edge-to-edge interlocking means could be employed within the 
scope of this invention. Moreover, the size of the panels, the materials 
used for the core and the skins, the hold down means, and other variable 
parameters may be varied within the scope hereof. 
This invention is clearly new and useful, and it was not obvious to those 
of ordinary skill in this art at the time it was made, in view of the 
prior art considered as a whole as required by law. 
It will thus be seen that the objects set forth above, and those made 
apparent from the foregoing description, are efficiently attained and 
since certain changes may be made in the above construction without 
departing from the scope of the invention, it is intended that all matters 
contained in the foregoing construction or shown in the accompanying 
drawings shall be interpreted as illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween. 
Now that the invention has been described,