<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Bruce,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As a starting point, I’d recommend reviewing the sections of the SolarABC’s Expedited Permit Process Report – REV 2.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://solarabcs.org/about/publications/reports/expedited-permit/index.html">http://solarabcs.org/about/publications/reports/expedited-permit/index.html</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>In it Bill has a section on structural reviews and possible reassurances that may be relevant for you.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Good Luck,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Glenn Burt<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Bruce Leininger<br><b>Sent:</b> Saturday, July 06, 2013 6:04 PM<br><b>To:</b> RE-wrenches@lists.re-wrenches.org<br><b>Subject:</b> [RE-wrenches] Structural Review for Residential PV Systems<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>A local jurisdiction is starting to require that we document non-truss rafter dimensions, span and attachment points. This seems to be a fad that other jurisdictions have required at times, and other times not. When the existing structure was deemed insufficient, we've either paid a structural engineer to do some calcs and recommend more attachment points, or sistered the rafters to match the spacing given in the 20 psf table in the UBC.<br><br>Would the dead load from the PV modules ever be more than that from adding a second layer of comp roofing, which does not require a structural analysis? Would the live point loads from the PV system ever be greater than the point load of a person walking on the roof? If the answers are "no" and "no", then it seems that a roof that supports a person walking on it would not be adversely affected by the installation of a non-ballasted residential PV system.<br><br>I looking for help with the following:<o:p></o:p></p><p class=MsoNormal>1. Has there been an occasion when a residential PV system (non-ballasted), that was installed per the manufacturer's instructions, detached from a roof or caused damage to the structure of the roof?<br>2. Is there a good explanation for why structural review for residential PV systems is necessary?<br>3. Are there studies or resources that I can present to building officials to explain why structural review for residential PV systems is not necessary?<o:p></o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Thanks for your help.<br><br>Bruce<o:p></o:p></p></div></body></html>