Standing-seam roof panel system

A standing-seam roof system with elevated sub-purlins supported on concealed slip assemblies is provided. A uniform thermal-insulating value of the roof system is maintained by elevating the roof panels substantially above the undeformed depth of the thermal-insulating blanket. Each clip assembly consists of two parts allowing level adjustment after the fastening of the clip assembly.

FIELD OF INVENTION 
This invention relates to metal roof panel systems and more particularly to 
standing-seam roof panel systems where adjacent sheet-metal panels have 
interlocking edges. 
BACKGROUND OF THE INVENTION 
Standing-seam roofs are widely used in commercial and high-quality 
residential building construction. Water-tightness of such roofs is 
ensured by providing standing seams at the edges of the sheet-metal 
panels, making fastener penetration through the surfaces of the panels 
unnecessary. 
A typical standing-seam roof system includes spaced-apart purlins to secure 
and support the roof panels, a blanket of insulating material overlaying 
the purlins, and roof panels overlaying the insulating blanket. 
A typical roof panel consists of a generally-flat surface, twelve inches to 
thirty inches wide, and two upstanding side legs forming a male profile on 
one side and a female profile on the other side. The panel is typically 
cold-formed from precoated metal having a thickness ranging from 0.016 
inch to 0.05 inch. 
The roof surface is typically formed by multiple panels engaged 
side-by-side and assembled in the following sequence. First, a 
thermal-insulating blanket is placed over the supporting roof purlins. A 
panel is then placed in position over the blanket. Clips holding the 
male-profiled leg of the panel in position are then fastened beside the 
panel edge to the supporting purlins through the thermal-insulating 
blanket. Finally, the female-profiled leg of the next panel is placed over 
the installed clips and caused to mechanically interlock with the 
male-profiled leg of the installed panel, using either a snap engagement 
profile design or a joint seaming machine. These steps are repeated until 
the entire roof area is covered. 
Water leakage through the panel surface is prevented by elimination of 
fastener holes in the panel surface. Water leakage through the seams is 
prevented by the height of the seam legs and, optionally, a resilient seal 
along the panel seam. 
The clips holding the panels to the supporting purlins are slidably engaged 
with the panel seams in the longitudinal direction, allowing free thermal 
movements of the panels and leading to long-lasting seal integrity. The 
upstanding seam profiles provide bending strength and stiffness against 
snow load and wind load. Wind uplift load is resisted by the hold-down 
clips. The interlocked seam provides resistance against separation under 
loads. 
While this prior art system has performed well and met substantial 
commercial success, there are several drawbacks of the system that could 
be eliminated. First, the thermal-insulating blanket is compressed by the 
roof panels at the purlin locations. Blanket compression impairs the 
thermal efficiency of the insulation and in some cases leads to interior 
water condensation in cold weather. The compression of the 
thermal-insulating blanket is magnified by snow load on the roof. Blanket 
compression can also cause a visible distortion of the flat surface of the 
roof panel over the purlin locations, resulting in poor appearance. 
A second drawback is that the precision-fit seams between roof panels 
require a close alignment tolerance on the purlins. The required purlin 
tolerance is not achievable using standard construction techniques. The 
prior art solution to this problem has been to use shims under the 
fastening clips; however, due to the compressibility of the 
thermal-insulating blanket, it is very difficult to predetermine the 
amount of shimming required before the clips are fastened down. As a 
result, time-consuming readjustments are often required. 
Thus, a need presently exists for a standing-seam roof system which 
maintains the functional features of the prior art system while 
eliminating these drawbacks.

SUMMARY OF THE INVENTION 
The present invention is related to a standing-seam roof system. The 
assembled roof system includes multiple, spaced-apart roof purlins, a 
thermal-insulating blanket overlaying the roof purlins, clip assemblies 
providing support to sub-purlins positioned above the thermal-insulating 
blanket, each sub-purlin spanning the width of an individual roof panel as 
well a holding down the upstanding seams of the roof panels at the roof 
purlins, and multiple standing-seam roof panels engaged in a side-by-side 
fashion with mechanically-interlocked seams and vertically supported on 
top of the sub-purlins. 
Each clip assembly comprises a top clip and a base clip slidably engaged in 
the vertical direction. (As used herein, the term "vertical" means in a 
direction perpendicular to the plane of the roof surface, and "horizontal" 
means in a direction parallel to the plane of the roof surface.) The top 
clip serves three functions holding down the male-profiled leg of the roof 
panel; engaging and supporting the sub-purlins; and permitting adjustment 
of the elevation of the erected roof surface The hold-down structure of 
the top clip allows free thermal movements of the roof panel in the 
longitudinal direction. The base clip consists of a vertical leg and a 
horizontal base flange and serves three functions: confinement of the top 
clip for vertically-slidable engagement; locking engagement with the top 
clip; and engagement of the clip assembly to a roof purlin. 
Each sub-purlin consists of at least one top flange to provide the bearing 
surface for the roof panel and at least one vertical web to provide 
strength and stiffness of the sub-purlin. For structural efficiency, it is 
preferred to provide at least one bottom flange in the profile of the 
sub-purlin, along with two webs and two outwardly-extending top flanges. 
The lengths of the flanges match the width of the roof panel, while the 
webs are extended beyond the width of the roof panel at both ends to form 
end tabs which are compatible with vertical slots in the top clip portion 
of the clip assembly for horizontally-slidable engagement. 
The installation procedure for the roof system includes the following steps 
exercised in sequence. 
First, place the thermal-insulating blanket over the roof purlins. 
Next, engage simultaneously the hold-down device of a clip assembly with 
the male-profiled leg of the roof panel and the vertical slots in the clip 
assembly with the end tabs of a sub-purlin, and fasten the base clip 
portion of the clip assembly through the thermal-insulating blanket into 
the roof purlin. In this step, the relative horizontal positions among the 
panel seam, sub-purlin, and the top clip portion are fixed. 
Then adjust the vertical position of the male-profiled leg by vertically 
sliding the top clip portion relative the base clip portion and then by 
locking a deformable tab in the base clip portion into the nearest of 
several spaced-apart horizontal slots in the top clip portion. These steps 
are repeated at all roof purlin locations along the length of the roof 
panel. 
Next, engage the left end of a new piece of sub-purlin into the vertical 
slots of an installed top clip portion. Repeat this step at all purlin 
locations along the length of the roof panel. 
Engage the female-profiled leg of a new panel with the male-profiled leg of 
the just-installed panel. 
Repeat the above steps until the entire roof area is covered. Finally, 
mechanically lock the female-profiled leg with the male-profiled leg for 
all seams using a roof seaming machine. This last step is not required in 
the case of a snap-lock seam design. 
It can be seen that all the prior art drawbacks are eliminated by way of 
this invention. The sub-purlins supporting the roof panels are elevated 
above the thermal-insulating blanket, preventing compression of the 
thermal-insulating blanket and thus preserving a uniform 
thermal-insulating value over the entire roof area. The top flanges of the 
sub-purlin provide firm and even support for the panel, thus preventing 
pillowing of the roof panel. The elevation adjustment is made after the 
fastening of the clip assembly, eliminating the installation difficulties 
of the prior art system. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
It was the design goal of the present invention to provide a standing-seam 
roof system having the following attributes: 
1. Panel supports elevated above the thermal-insulating blanket such that 
the thermal-insulating value will not be impaired due to compression of 
the insulating blanket. 
2. Metal sub-purlins to provide an even and rigid support of the flat 
portion of the roof panel surface. 
3. Concealed connection clips allowing free longitudinal thermal movement 
of the roof panel and being sandwiched between the male-profiled leg of 
each panel and the female-profiled leg of its adjacent panel. 
4. Two-part clip design allowing alignment adjustment after the fastening 
of the connection clip without the use of additional fasteners or shims. 
5. Easy installation of sub-purlins without the use of additional 
fasteners. 
Referring initially to FIG. 1, a typical prior art standing-seam roof 
system 10 adaptable to the present invention includes panel 10a having a 
generally flat central portion 11 with optional longitudinal stiffeners 
12, one upstanding side leg 13 with male-profiled portion 14, and another 
upstanding side leg 15 with female-profiled portion 16. The 
female-profiled portion 16 is designed to mechanically interlock with the 
male-profiled portion 14 of the adjacent panel in a snap-engagement 
fashion. Clips 17 join the panels to purlin 18 by way of fasteners 19 and 
shims 19a. Thermal-insulating blanket 19b is compressed between central 
portion 11 and purlin 18. The present invention is adaptable not only to 
the type of snap-lock design shown in FIG. 1 but also to a machine-seamed 
seam design. The cover width of the panel 10a normally ranges from twelve 
inches to thirty inches. Commonly used materials include pre-coated steel, 
pre-coated aluminum, copper and stainless steel. The metal thickness 
normally ranges from 0.016 inch to 0.05 inch. 
Referring now to FIG. 2, sub-purlin 20 of the present invention includes 
two top flanges 21, two vertical webs 22, and one bottom flange 23. The 
length of the flanges 21 and 23 is designed to be equal to or slightly 
less than the cover width of the panel 10a. The webs 22 are extended at 
both ends to form vertical end tabs 24. The sub-purlin 20 is preferably 
cold-formed from steel of thickness ranging from 0.03 inch to 0.06 inch. 
Many other equivalent profiles for the sub-purlin will be suggested to 
those skilled in the art. 
Referring now to FIGS. 3 and 4, top clip portion 30 consists of a vertical 
leg 35 and a top lip 31. The top clip portion 30 (FIG. 3) provides three 
functional features, namely, a top lip 31 to hold down the male-profiled 
portion 14 of the panel 10a, sub-purlin supporting slots 32 to engage the 
end tabs 24 and lock the sub-purlin 20 into position, and level-adjusting 
horizontal slots 33. The base tabs 34 are provided to keep the top clip 
portion 30 from separating from the preassembled clip assembly 50 (FIG. 
4). The top clip portion 30 is preferably formed from steel of thicknesses 
ranging from 0.036 inch to 0.06 inch. 
The base clip portion 40 (FIG. 3) consists of a horizontal leg 41 and a 
vertical leg 42. A screw hole 43 is provided in the horizontal leg 41. At 
the top portion of the vertical leg 42, vertical edge slots 44 are formed 
by wrapped-around edge lips 45. At the middle portion of the vertical leg 
42, an integral deformable horizontal tab 46 is provided. The edge slots 
44 are designed to contain the vertical leg 36 of the top clip portion 30 
in a slidable engagement fashion. The horizontal tab 46 is designed to 
lock into one of the level adjusting slots 33 of the top clip portion 30. 
Embossed stiffeners 47 are preferable in order to increase the stiffness 
of the base clip portion 40. The base clip 40 is preferably made from 
steel in the thicknesses ranging from 0.036 inch to 0.06 inch. 
FIG. 4 shows the preassembled clip assembly 50 comprising the top clip 
portion 30 and the base clip portion 40 in a vertically slidable 
relationship. 
In operation, as shown in FIG. 5, the first step in the installation is to 
hook the top clip portion 30 on the male-profiled portion 14 of the panel 
10a on the left and to engage the end tabs 24 of the sub-purlin 20 on the 
left simultaneously. The second step is to fasten the base clip portion 40 
to the roof purlin 64 using the screw 61. Rigid insulating block 62 may be 
used to absorb variations in the design depth of the insulating blanket 
63. The third step is to slide the top clip portion 30 up or down to the 
desired level, then, the horizontal tab 46 of the base clip portion 40 is 
pressed into the nearest level adjusting slot 33 of the top clip portion 
30 to lock the entire fastening system in position. The above three steps 
are repeated at all roof purlins along the length of the roof panel 10a. 
The fourth step is to engage the sub-purlins 20 on the right into the 
vertical slots 32 of the installed top clip portion 30 along the length of 
the roof panel 10a. The fifth step is to engage the female-profiled 
portion 16 of the next panel 10a on the right with the male-profiled 
portion 14 on the installed panel 10a on the left. Then, the erection 
processes are repeated for the newly-placed panel 10a. 
It can thus be seen that the roof panels 10a are rigidly supported on 
sub-purlins 20 which are elevated above the insulating blanket 63, 
eliminating the impairment of the thermal insulation value of the prior 
art system due to a compression of the insulating blanket. It can also be 
seen that the alignment adjustments are performed after the fastening of 
the base clip portion 40, thereby eliminating the difficulties of 
adjustments in the prior art system. 
While I have illustrated and described certain preferred embodiments of the 
present invention, it is to be understood that the invention is not 
limited thereto, and numerous equivalent constructions may be embraced 
within the scope of the following claims.