Re: [RE-wrenches] Module Racking Attachment to SIP Roof
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 g...@icarussolarservices.com mailto:g...@icarussolarservices.com On 7/26/2011 8:09 AM, penobscotso...@midmaine.com 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 (8x8) 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 Design Fellow 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 g...@icarussolarservices.commailto:g...@icarussolarservices.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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
Re: [RE-wrenches] Module Racking Attachment to SIP Roof
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 (8x8) 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 Design Fellow 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 g...@icarussolarservices.com mailto:g...@icarussolarservices.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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
Re: [RE-wrenches] Module Racking Attachment to SIP Roof
One problem that came up on a project recently, is that your penetrations (as proposed in your solution below) will essentially ruin the thermal performance of the SIPs system. The whole point of the SIPs system is that there are no thermal short circuits such as framing members that allow heat to be transmitted around all that insulation. The project I was referring to was with NREL, and a smart engineer caught it, and forced the PV contractor to mount in a way without penetrations. I also work with very savvy architects that are now specifying minimal penetrations through the thermal envelope. I'd suggest a standing seam roof, with S5 clamps. Ask the roofer to use extra attachment screws, if you're worried. R. Walters r...@solarray.com Solar Engineer 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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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
Re: [RE-wrenches] Module Racking Attachment to SIP Roof
Gary Has anyone checked with the SIP manufacturer, this is a laminated structure and will have more holding power than simple sheathing between rafters (which is still doable with larger mounting plates and multiply short screws). It could be that they have performed shear and pull out tests when mounting directly to the sheathing. SIP's are engineered and you should be able to find engineering data to justify a mounting system. The bolt through with steel plates on both sides sounds like overkill to me, even if the pull out was less than needed doubling up or tripling up screwed plates on the surface designed for holding into sheathing seems the better solution, a lot less labor in the long run. Bill On Tue, Jul 26, 2011 at 11:48 AM, R Ray Walters r...@solarray.com wrote: One problem that came up on a project recently, is that your penetrations (as proposed in your solution below) will essentially ruin the thermal performance of the SIPs system. The whole point of the SIPs system is that there are no thermal short circuits such as framing members that allow heat to be transmitted around all that insulation. The project I was referring to was with NREL, and a smart engineer caught it, and forced the PV contractor to mount in a way without penetrations. I also work with very savvy architects that are now specifying minimal penetrations through the thermal envelope. I'd suggest a standing seam roof, with S5 clamps. Ask the roofer to use extra attachment screws, if you're worried. R. Walters r...@solarray.com Solar Engineer 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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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 -- Bill Hoffer PE NABCEP Certified Solar PV Installer™ Sunergy Engineering Services PLLC 2504 Columbia Ave NW East Wenatchee WA 98802-3941 suneng...@gmail.com Cell:(509)679-6165 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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
Re: [RE-wrenches] Module Racking Attachment to SIP Roof
Seems as though a motivated Architect could order custom SIP panels with dimensioned lumber ribs attached on the inside surface of the exterior roof panel. It would allow for NS rows of attachments without puncturing the envelope. We priced SIP construction years ago and found that mfgrs can build virtually any wall or roof panel configuration the design requires. All it takes is more money. That's why we ended up with 2x6 with spray foam shell. Jim Duncan North Texas Renewable Energy NABCEP Certified Solar PV Installer No.031310-57 TECL 27398 nt...@1scom.net 817.917.0527 www.ntrei.com -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]On Behalf Of R Ray Walters Sent: Tuesday, July 26, 2011 1:49 PM To: g...@icarussolarservices.com; RE-wrenches Subject: Re: [RE-wrenches] Module Racking Attachment to SIP Roof One problem that came up on a project recently, is that your penetrations (as proposed in your solution below) will essentially ruin the thermal performance of the SIPs system. The whole point of the SIPs system is that there are no thermal short circuits such as framing members that allow heat to be transmitted around all that insulation. The project I was referring to was with NREL, and a smart engineer caught it, and forced the PV contractor to mount in a way without penetrations. I also work with very savvy architects that are now specifying minimal penetrations through the thermal envelope. I'd suggest a standing seam roof, with S5 clamps. Ask the roofer to use extra attachment screws, if you're worried. R. Walters r...@solarray.com Solar Engineer 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 attachment: North Texas Renewable Energy Inc.vcf___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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
Re: [RE-wrenches] Module Racking Attachment to SIP Roof
Jim: Your comment is very timely and apropos! Talked with the architect this morning about this as a possible solution. Since the SIPs are being custom manufactured, they can embed the ribs as you described. That's great for this project, but adding PV as a retrofit on an existing SIP roof will be a challenge. Other Wrenches: Thanks so much for your helpful comments and suggestions! Regards, Gary Willett, PE g...@icarussolarservices.com mailto:g...@icarussolarservices.com On 7/26/2011 10:45 PM, North Texas Renewable Energy Inc wrote: Seems as though a motivated Architect could order custom SIP panels with dimensioned lumber ribs attached on the inside surface of the exterior roof panel. It would allow for NS rows of attachments without puncturing the envelope. We priced SIP construction years ago and found that mfgrs can build virtually _any_ wall or roof panel configuration the design requires. All it takes is more money. That's why we ended up with 2x6 with spray foam shell. *Jim Duncan* *North Texas Renewable Energy* *NABCEP Certified Solar PV* *Installer No.031310-57* *TECL 27398* *nt...@1scom.net* mailto:nt...@1scom.net** *817.917.0527* *www.ntrei.com* http://www.ntrei.com/ ** -Original Message- *From:* re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]*On Behalf Of *R Ray Walters *Sent:* Tuesday, July 26, 2011 1:49 PM *To:* g...@icarussolarservices.com; RE-wrenches *Subject:* Re: [RE-wrenches] Module Racking Attachment to SIP Roof One problem that came up on a project recently, is that your penetrations (as proposed in your solution below) will essentially ruin the thermal performance of the SIPs system. The whole point of the SIPs system is that there are no thermal short circuits such as framing members that allow heat to be transmitted around all that insulation. The project I was referring to was with NREL, and a smart engineer caught it, and forced the PV contractor to mount in a way without penetrations. I also work with very savvy architects that are now specifying minimal penetrations through the thermal envelope. I'd suggest a standing seam roof, with S5 clamps. Ask the roofer to use extra attachment screws, if you're worried. R. Walters r...@solarray.com mailto:r...@solarray.com Solar Engineer 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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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
