Daryl: Sounds like we came to the same conclusion - bolt(s) through the SIPs is the only way to go. I'll discuss this with builder - I'm not sure how the underside will be finished out but I'm sure we can work it out. Thanks for the response!
Regards, Gary Willett, PE Icarus Engineering / Solar Services LLC NABCEP Certified Solar PV Installer # 031310-246 [email protected] <mailto:[email protected]> On 7/26/2011 8:09 AM, [email protected] wrote:
Hi Gary, We've done several SIP projects and I've done the same research you are now likely doing. What I ended up designing was a system of aluminum plates (8"x8") that screwed into the roof sheathing at four points with 1/4" ss lag screws, then using 1/2 threaded rod that ran through the center of the plate through the SIP to a similar plate mounted on the inside. We used bituthane between the plate and the roof, as well as silicone, then used standard racking with flashing. The oldest SIP job we have is now going on seven years with no problems at all. Feel free to contact me off list if you have any questions about this. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar DesignFellow Wrenches: Working on a residential PV design using Structural Insulated Panels, or SIP panels. Preliminary design is three AC strings of 17 microinverters, in three portrait rows ~18" apart. The good news is that the builder wants to include the PV as part of the original construction. The wood structural roof beams on which the SIPs will rest are on 20 foot centers, and run the same direction as the portrait PV modules. The SIPs are 10-1/4" thick, with 5/8" plywood on top and bottom. Roof pitch is 1.5:12 (low pitch). Are there any PV rack mounts specifically designed for a SIP structure? I've done a lot of web searches, and can find no specific products. I've looked at the Eco-Fasten^(TM) Universal Roof Attachment Bracket. It has 8 mounting holes per attachment point using #14 screws. Pull-out resistance will be low per attachment point with 5/8" plywood. One solution could be a product that had a bolt-plate on the bottom of the SIP, that penetrates the SIP with long 5/16" threaded bolt(s), and then attaching to the PV mount at the top of the SIP. The UniRac SolarMount steel flat-top mount has four 5/16" bolt-holes and might be a good choice. This method should have no problem achieving the required pull-out resistance. Any suggestions, installation experience, on how to put PV on a SIP roof? -- Regards, Gary Willett, PE Icarus Engineering / Solar Services LLC NABCEP Certified Solar PV Installer # 031310-246 [email protected]<mailto:[email protected]> _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options& settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules& etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
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