<font size="2"><font face="arial,helvetica,sans-serif">There is a big difference between standing seam metal roofs and surface screwed metal roofs. With surface screwed (aka ProPanel or Ag Panel), screws penetrate through the roof skin and rely upon a neoprene gasket under a cupped </font></font><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">washer to provide the weather-tight seal. It makes a pretty good seal and I've used it on my own home, but I don't think I'd use it in Montana and I sure wouldn't try to attach PV over it. The days of lagging L feet through the roof deck are thankfully waning, and there is </span><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">almost no practical way to use a flashed method of mounting with surface screwed metal.</span><div>
<font class="Apple-style-span" face="arial, helvetica, sans-serif"><br></font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif">With standing seam roofs, the metal is formed into long U shaped pans. As each pan is installed, the roofer nails L shaped "clips" to the deck with one side of the clip butted up against the latest pan. The next pan is </font><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">butted up against the first, which captures the clip between the two. The </span><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">upward facing legs of the U (and clip) are then crimped and folded over, locking them together and </span><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">forming a watertight seal</span><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">. I had a standing seam roof on my home in Cincinnati -- eighty years old and still going strong. </span></div>
<div><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; "><br></span></div><div><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">The biggest challenge with attaching PV to standing seam roofs is not how well the modules are attached to the skin, but how well the skin is attached to the structure. Read the archives, but in the end this really comes down to how close the roofer installed the clips. This is where the 4" that Andrew mentioned comes into play (seems a little excessive to me, but what the heck, I'm not a roofing dude and this isn't something you want to do twice). </span><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">The dream scenario part comes in when you realize that YOU get to drive the bus on how closely the clips are installed, as opposed to being presented with a roof where you have no idea how many clips were used, what the spacing is, or even whether nails or screws or bubble gum were used to connect them to the deck. The folks that make the S-5 clamp know metal roofs, and they can help you determine what spacing works for your application. Get that into the contract, and make sure someone is on site providing oversight when the roof is installed.</span></div>
<div><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; "><br></span></div><div><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">As far as some of the other options which were presented -- yes, lagging into engineered I-beams is probably not a good idea without checking with the manufacturer, but </span><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">adding a second layer of ply doesn't suddenly make a structural base for lag screws. Lag screw pull-out resistance is provided by inches of thread embedded into solid wood, and shiners (fasteners that poke through the deck into the attic space) won't give any real strength. If it's really 1/2" ply, adding a layer of 3/4 ply would give you 1-1/4" of "wood" -- do the math and see if that's enough for your climate. Adding 2x blocking would be an option if you have access to the attic, but you need to make sure the loads transfer to the rafters (I-beams), rather than concentrate on the deck. Nailing the blocking would be fine -- after all, that's how houses are built. Lagging the blocking as suggested by someone earlier, however, will not only be insanely difficult but risk splitting the top chord of the beam. If you split that, I would immediately stop what you're doing and consult with the I-beam manufacturer. Big liability moment there.</span></div>
<div><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; "><br></span></div><div><span class="Apple-style-span" style="font-family: arial, helvetica, sans-serif; ">But I'd avoid all that lags, nails, plywood and blocking entirely, put on a standing seam metal roof with adequate clips and install the PV with S-5 clamps.</span></div>
<div><div><div><font size="2"><font face="arial,helvetica,sans-serif"><br></font></font></div><div><font size="2"><font face="arial,helvetica,sans-serif">My .02</font></font></div><div><font size="2"><font face="arial,helvetica,sans-serif"><br clear="all">
</font></font>Phil Undercuffler<div><br></div><div><div><font face="arial, sans-serif"><span style="border-collapse:collapse"><br></span></font></div></div><br>
<br><br><div class="gmail_quote">On Thu, Oct 21, 2010 at 11:52 AM, benn kilburn <span dir="ltr"><<a href="mailto:benn@daystarsolar.ca">benn@daystarsolar.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div>
andrew,<div>a few comments added to your last email...</div><div><br></div><div><p style="text-indent:0px !important;margin-top:0px !important;margin-right:0px !important;margin-bottom:0px !important;margin-left:0px !important;padding-top:0px !important;padding-right:0px !important;padding-bottom:0px !important;padding-left:0px !important">
You Wrote.... </p><p style="text-indent:0px !important;margin-top:0px !important;margin-right:0px !important;margin-bottom:0px !important;margin-left:0px !important;padding-top:0px !important;padding-right:0px !important;padding-bottom:0px !important;padding-left:0px !important">
If you ask me this is a dream scenario. The scary thing about S-5!s is that you rarely know how often the roofing panels are attached to the decking and how well the decking is attached to the framing. <font color="#0070C0">i'm not overly familiar with standing seam metal roofs (and i know they are not all created equal) but aren't the screws holding the metal roof panel to the decking visible at the bottom, at the top under the vent cap and anywhere along the length of said panel? i agree about the 'unknown' attachments btwn the decking and the framing </font> In this case you can direct the roofer to fasten the roof as often as you want. I had a PE do an analysis for a sure-fire acceptable attachment method for a standing seam roof given: 90 mph wind zone, 18" wide standing seam roofing panels, flush-mounted PV array (modules to rail to S-5!s, no tilt legs), and his result was that if the roofing panels are fastened every 4" along each seam you are in the clear. <font color="#0070C0">No doubt, that seems like quite a few fasteners.</font> He did not address the decking-to-framing attachment, <font color="#0070C0">So worst case scenario, you get a 90+ mph wind that takes the array, the metal roof <u>and the decking</u> for a ride to the ground,</font><span style="color:rgb(0, 112, 192)"> (HAS ANYONE SEEN OR HAD THIS HAPPEN?) </span><font color="#0070C0">when it is determined that the decking wasn't properly attached to the framing, who do ya call? PV installer, PE who stamped it, roofer? I'm not looking for a place to point fingers, I'm just looking for some insight on this so i understand our responsibilities a bit better. I realize that it would be onerous to confirm the number and placement of decking to framing attachments) </font>but while the roof is off you could add as many fasteners as you want. If the structure of the roof is in question I would definitely have a PE look at it and stamp the plans before proceeding, but once you have everything under the roof robust and approved, you are primed and ready for a worry-free, penetration-free S-5!-to-standing-seam array install.</p>
<div class="im"><p style="text-indent:0px !important;margin-top:0px !important;margin-right:0px !important;margin-bottom:0px !important;margin-left:0px !important;padding-top:0px !important;padding-right:0px !important;padding-bottom:0px !important;padding-left:0px !important">
In another email string someone mentioned issues with S-5!s slipping down the roof due to snow which is why I recommend attaching at every seam and breaking out that torque-wrench when installing. <br style="text-indent:0px !important">
</p><p style="text-indent:0px !important;margin-top:0px !important;margin-right:0px !important;margin-bottom:0px !important;margin-left:0px !important;padding-top:0px !important;padding-right:0px !important;padding-bottom:0px !important;padding-left:0px !important">
Good luck!</p></div>...end of your msg</div><div><br></div><div>in response to Kris' suggestion, don't the 2x6's need to be toe-nailed into the 'rafters' on either side? or in this case toe-nailed into the beams? which probably wouldn't be much different than the 'inadvisable' lag bolting into them.</div>
<div><br></div><div>cheers,</div><div><div class="im">benn<br><span style="color:rgb(0, 32, 96)"><font face="'Franklin Gothic Medium'">DayStar Renewable Energy Inc. </font></span><div><div><font face="'Franklin Gothic Medium'"><a href="mailto:benn@daystarsolar.ca" target="_blank">benn@daystarsolar.ca</a></font></div>
<div><font face="'Franklin Gothic Medium'">780-906-7807 </font></div><div><font face="'Franklin Gothic Medium'">HAVE A SUNNY DAY
</font></div><div><br></div></div><br><br><br><br><hr></div>From: <a href="mailto:atruitt@gmail.com" target="_blank">atruitt@gmail.com</a><br>Date: Thu, 21 Oct 2010 11:30:40 -0600<br>To: <a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a><div>
<div></div><div class="h5"><br>Subject: Re: [RE-wrenches] The perfect solar ready roof<br><br><br>
If you ask me this is a dream scenario. The scary thing about S-5!s is that you rarely know how often the roofing panels are attached to the decking and how well the decking is attached to the framing. In this case you can direct the roofer to fasten the roof as often as you want. I had a PE do an analysis for a sure-fire acceptable attachment method for a standing seam roof given: 90 mph wind zone, 18" wide standing seam roofing panels, flush-mounted PV array (modules to rail to S-5!s, no tilt legs), and his result was that if the roofing panels are fastened every 4" along each seam you are in the clear. He did not address the decking-to-framing attachment, but while the roof is off you could add as many fasteners as you want. If the structure of the roof is in question I would definitely have a PE look at it and stamp the plans before proceeding, but once you have everything under the roof robust and approved, you are primed and ready for a worry-free, penetration-free S-5!-to-standing-seam array install.<br>
In another email string someone mentioned issues with S-5!s slipping down the roof due to snow which is why I recommend attaching at every seam and breaking out that torque-wrench when installing. <br><br>Good luck!<span style="color:rgb(0, 102, 0)"></span><br>
<span style="color:rgb(0, 102, 0)"><br>Andrew Truitt</span><span style="color:rgb(0, 102, 0)"><br>NABCEP Certified PV Installer<span style="font-size:10pt;font-family:Arial">™</span> (ID# 032407-66)</span><span style="color:rgb(0, 102, 0)"></span><span style="color:rgb(0, 102, 0)"><br>
Truitt</span><span style="color:rgb(0, 102, 0)"> </span><span style="color:rgb(0, 102, 0)">Renewable</span><span style="color:rgb(0, 102, 0)"> </span><span style="color:rgb(0, 102, 0)">Energy</span><span style="color:rgb(0, 102, 0)"> </span><span style="color:rgb(0, 102, 0)">Consulting</span><span style="color:rgb(0, 102, 0)"><br>
(202) 486-7507</span><br>
<a href="http://www.linkedin.com/pub/andrew-truitt/8/622/713" target="_blank">http://www.linkedin.com/pub/andrew-<span>truitt</span>/8/622/713</a><br><br><span style="color:rgb(0, 153, 0)"><span style="font-size:11pt;color:rgb(31, 73, 125);font-family:Calibri"></span></span><br>
<br>"Don't get me wrong: I love nuclear energy! It's just that I prefer
fusion to fission. And it just so happens that there's an enormous
fusion reactor safely banked a few million miles from us. It delivers
more than we could ever use in just about 8 minutes. And it's wireless!"<br>
<br>~William McDonough<br><br><br>
<br><br>
On Wed, Oct 20, 2010 at 2:32 PM, Kristopher Schmid <<a href="mailto:solman@legacysolar.com" target="_blank">solman@legacysolar.com</a>> wrote:<br>
<blockquote><font color="#0000ff">What about screwing in double 2x6s flush to the roof deck between the beams where your feet will attach and lag bolting into that? Definitely check with the beam manufacturer first, though.</font><br>
<br>
<font color="#0000ff">Kris</font><br>
Legacy Solar<br>
864 Clam Falls Trail<br>
Frederic, WI 54837<br>
715-653-4295<br>
<a href="mailto:solman@legacysolar.com" target="_blank">solman@legacysolar.com</a><br>
<a href="http://www.legacysolar.com" target="_blank">www.legacysolar.com</a> <br>
</blockquote>
<blockquote><blockquote>-----Original Message-----<br>
<b>From:</b> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a> [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Scott McCalmont<br>
<b>Sent:</b> Wednesday, October 20, 2010 12:00 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] The perfect solar ready roof<br>
In general, you shouldn't drill or cut the flanges on engineered wood beams. I think that eliminates lag screws into the rafters. They probably wouldn't have the same pull-out strength as a lag screw into a conventional rafter, either. <br>
<br>
Scott<br><br>
On Oct 19, 2010, at 7:58 PM, Chris Daum wrote:<br>
</blockquote>
</blockquote>
<br>
<br>
<br><blockquote><span style="word-spacing:0px;font:medium Helvetica;text-transform:none;text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate">
<div lang="EN-US">
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span>Dear Wrenches:</span></font></div>
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span></span></font></div>
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span>I have a composite (shingle) roof at hand, and the
owner wants to upgrade it to a metal roof and install a 5kw+ array on
it. The rafters are those (sort of) particle board I-beams
covered with 1/2" plywood (and shingles). What's the best metal
roofing you could suggest--and would you beef up the wood to lag
into?</span></font></div>
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span></span></font></div>
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span>Thanks for all your
input.</span></font></div>
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span></span></font></div>
<div dir="ltr" align="left"><font color="#800000" face="Comic Sans MS"><span>
<div align="left">
<div align="left"><font size="2" color="#000080" face="Comic Sans MS">Chris
Daum</font></div>
<div align="left"><font size="2" color="#000080" face="Comic Sans MS">Oasis
Montana Inc.</font></div>
<div align="left"><font size="2" color="#000080" face="Comic Sans MS">406-777-4309</font></div>
<div align="left"><font size="2" color="#000080" face="Comic Sans MS">406-777-0830
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