<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Do you know the wind loading vs pull-out resistance of the threads?</div>This is why I am happy to have the services of a structural engineer, as required by our County for all roof-mounts for the last 4 years or so. At first it was an annoyance to have the extra time and expense of a PE analysis for each job, but now that it's incorporated into our practices, I certainly sleep better during windstorms. We often have to provide more attachments than our seat-of-the-pants approach would have resulted in, but we no longer have liability for it.<div><br></div><div>I imagine your threaded proposal is based on the lack of access to the underside of the roof for a through-bolted solution. There has been some discussion in the past of toggle type fasteners for this situation. </div><div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Palatino; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div>Bruce Erickson</div><div>Mendocino Solar Service</div><div>PO Box 1252</div><div>Mendocino, CA 95460</div><div>707-937-1701</div><div><br class="webkit-block-placeholder"></div></span><br class="Apple-interchange-newline">
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<br><div><div>On Apr 21, 2011, at 2:27 PM, North Texas Renewable Energy Inc wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
<div>
<div><span class="312590421-21042011"></span><span class="312590421-21042011"><font face="Arial">Wrenches </font></span></div>
<div><span class="312590421-21042011"><font face="Arial"></font></span><span class="312590421-21042011"><font face="Arial"></font></span> </div>
<div><span class="312590421-21042011"><font face="Arial">I'm proposing a PV array on
a metal building with L feet attached directly thru the roof into
the purlins. The plan is to use thread cutting SS bolts, a minimum of ¼-28
pitch. The metal is 14 ga and will engage over 2 full threads and
because the array is only 2 landscape modules on NS rails there will be 2
bolts for every module. 36 total. Im using a mag base drill press so the144
holes will be straight & round. </font></span></div>
<div><span class="312590421-21042011"><font face="Arial">What surprises can I expect
or is there an easier way to go about this. Your 2¢ is welcome.
</font></span></div>
<div><span class="312590421-21042011"><font face="Arial"></font></span> </div>
<div><span class="312590421-21042011">
<div><font size="2"><font face="Arial"><strong>Jim
Duncan</strong></font></font></div>
<div><font face="Arial" size="2"><strong>North Texas Renewable
Energy</strong></font></div>
<div><font face="Arial" size="2"><strong>486 W.N. Woody Road</strong></font></div>
<div><font face="Arial" size="2"><strong>Azle Texas 76020</strong></font></div>
<div>
<div>
<div><font face="Arial" size="2"><strong>NABCEP Certified Solar
PV</strong></font></div>
<div><font face="Arial" size="2"><strong>Installer
No.031310-57</strong></font></div>
<div><font face="Arial" size="2"><strong>TECL
27398</strong></font></div></div></div>
<div><a href="mailto:ntrei@1scom.net"><font face="Arial" size="2"><strong>ntrei@1scom.net</strong></font></a><font face="Arial" size="2"><strong> </strong></font></div>
<div><font face="Arial" size="2"><strong>817.917.0527</strong></font></div>
<div><a href="http://www.ntrei.com/"><font face="Arial" size="2"><strong>www.ntrei.com</strong></font></a></div>
<div><font face="Arial" size="2"><strong></strong></font> </div><font face="Arial"></font></span></div>
<div><span class="312590421-21042011"><font face="Arial"></font></span> </div></div>
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