Page
18
Unirac Code-Compliant Installation Manual
SunFrame
R
1411 Broadway Boulevard NE
Albuquerque NM 87102-1545 USA
If the standoff supporting the lowest rail is 1 inch taller than
the standoffs on the footing sliders, place both L-feet in the same
orientation—either both long side up or both short side up.
With standoffs of equal length, orient L-foot to compensate for
height difference.
Footing and splicing requirements
The following criteria are required for sound installations .
While short sections of rail are structurally permissible, they
can usually be avoided by effective planning, which also pro-
motes superior aesthetics . See “Material planning for rails
and cap strips” (p . 20) .
The installer is solely responsible for ensuring that the roof and
its structural members can support the array and its live loads.
A thermal break is required every 40 feet of continuously con-
nected rail. See Unirac Splices and Expansion Joints Installa-
tion Manual for details .
1 . Footing spacing along the rail (A in illustration above)
is determined by wind loading (see pp . 2–3, especially
step 1) .
2 . Overhang (B) must be no more than 1/3 the length of
the maximum footing spacing (A) . For example, if Span
(A) is 48 inches, Overhang (B) should not exceed 16
inches .
3 . Do not locate a splice in the center third of the span
between two adjacent feet .
4 . In a spliced length of rail, all sections must be support-
ed by no less than two L-feet .
5 . Rail sections longer than half the footing spacing re-
quire no fewer than two L-feet .
Using standoffs with L-foot adjusting sliders
Two-piece aluminum standoffs may be used with footing
sliders, although flashings may not be available to cover the
entire length of the slider . Use the bases of the standoffs
only in the lowest row . In subsequent rows, attach the shaft
of each standoff to the slider using the slider’s
3
/
8
-inch hex-
head bolt . Note that L-feet are positioned long side up on the
lowest rows and with long side down in subsequent rows—
in the same manner as an installation with no standoffs .
B
A
L-foot
This example assumes a rail seven times the length of the
footing spacing (A). A splice may be located in any of the
shaded areas. If more than one splice is used, be sure the
combination does not violate the following requirements:
Modules should always be fully supported by rails. In other words, modules
should never overhang rails. This is especially critical when supporting the
short side of a non-rectangular module. When a rail supports a pair of non-
rectangular modules by themselves (right), it must be supported by at least
two L-feet. The rail should be at least 14 and no more than 24 inches long,
which will likely require a stringer between rafters to ensure proper footings.
Non-rectangular modules
Rail
Rafters
Stringer
