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<font face="Times New Roman, Times, serif">We did one direct to S-5!
installation - never again. Alignment and leveling was a pain and
the wire retaining clips on the discs were useless</font>. Always
use rails. Aside from the installation issues, rails will better
distribute loads across the roofing seams. Without rails you'll
inevitably end up with "diving board" modules cantilevered off of
the clamps.<br>
<br>
But really, the most important point I can make is that the S-5!
clamps are only as good as the roofing. If you look in the S-5!
literature you'll find a wide variety of tension and shear force
ratings depending on the brand, material, and thickness of the
roofing. You are also dependent upon the diligence and skill of the
roofer. How many fasteners are under there, of what kind, and into
what sheathing? It's a gamble. My response is to distribute the load
with as many clamps as I can. You'll find that the resulting factor
of safety is not all that huge. The cost, as a percentage, is not
that huge either. And you'll sleep better.<br>
<br>
Hilton<br>
<pre class="moz-signature" cols="72">--
Hilton Dier III
Renewable Energy Design
Partner, Solar Gain LLC
453 East Hill Rd.
Middlesex, VT 05602
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