Friends:
Thanks for bringing up this scenario. I have two problems with using a product such as the easy-feet or other deck-fastened brackets, particularly on a rigid foam-above-sheeting roof: 1. I worry about compression of the foam material over time. This could leave a void under the bracket which could lead to leaks or wobbly brackets. 2. I don’t believe in chemical solutions for sloped-roof rain-proofing. By that I mean the use of caulks, gaskets, etc. Since roofs were first thatched, the overriding wisdom is that gravity is the only way to reliably shed water. Overlapping, seamless material is the only method to use. Caulks degrade, roof surfaces become powdery, and the rafter is often under an architectural feature or seam in the shingles. I researched the PLP EZ foot back when the company was DPW. The fasteners provided were not rated for the application, according to the fastener manufacturer. If you can match the fasteners to the decking and the forces, then maybe you have a start to a mounting solution. Whatever product you use, I would install it on a section of flashing metal, lapped under the next course up. The flashing gives a flat, seamless surface to caulk or gasket to. The thicker and wider the flashing, the more you distribute the downward force applied to the bracket by weight and fasteners. Any voids under the bracket will have an overlapped flashing above it. I hope these musings help you find a solution. William Miller PS: I have encountered this roof configuration a few times on flat, built-up roofing (BUR <https://homeinspectioninsider.com/built-up-roofing/>). We have dealt with it by cutting through the foam, installing blocking on top of the sheeting and having a roofer feather the blocks into the roofing with cant strips <https://www.blueridgefiberboard.com/cant-strip-tapered-edge-smoothes-roof-drainage-slope/>. A pitched roof is a different situation, however. Wm Miller Solar 17395 Oak Road, Atascadero, CA 93422 805-438-5600 www.millersolar.com CA Lic. 773985 *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *August Goers via RE-wrenches *Sent:* Wednesday, March 29, 2023 11:47 AM *To:* RE-wrenches *Cc:* August Goers *Subject:* Re: [RE-wrenches] Attaching Array To or Through Ply We've found that in the Bay Area that deck-mount solutions typically pencil out structurally (via a structural professional engineer) as long as the deck is 1/2" plywood or thicker, assuming we have all the info on how the roof is constructed. The big assumption is that we can get all that roof construction info, which can be difficult for existing structures. We haven't taken the plunge yet on the flahingless deck mount products like the Sunmodo Nanomount or Unirac Flashloc Duo. I do think that they offer several significant advantages including not needing to find rafters, thus virtually eliminating missed pilot holes, and not disturbing the comp shingle by eliminating prying up the courses to insert the flashing. August Luminalt On Wed, Mar 29, 2023 at 11:34 AM Solar Energy Solutions via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: We like Spider Rax… with the flashing! *Spider-Rax PV Solar Mounting <https://spiderrax.com/>* *spiderrax.com <https://spiderrax.com/>* *Error! Filename not specified.* <https://spiderrax.com/> *Andrew Koyaanisqatsi* President *Solar Energy Solutions, Inc.The BRIGHT CHOICE* *Since 1987, helping you and your * *Portland neighbors move towards an environmentally sustainable future.* *503-238-4502 <503-238-4502>www.SolarEnergyOregon.com <http://www.solarenergyoregon.com/>* On Mar 29, 2023, at 11:04 AM, Jerry Shafer via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Wrenches Sounds like a SIP's type product, there are quite a few multi hole attachment bases that are designed for SIP's. Most will have a larger base, lots of holes for screws to attach that do not require rafters underneath to attach. Fun times On Wed, Mar 29, 2023, 8:30 AM frenergy via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Matt, I guess my questions are 1/2" plywood or 5/8" and how thick is the foam? Oh and I assume its nominal 2X6 T&G? Do you know how the plywood is attached?.....through the foam into the T&G?... to stringers, nailers or whatever they're called? Bill Feather River Solar Electric Bill Battagin, Owner 4291 Nelson St.(shipping) 5575 Genesee Rd. (USPS, UPS) Taylorsville, CA 95983 530.284.1925 Office/ 530.258.1641 Cell CA Lic 874049 Solar powered since 1982 On 3/29/2023 7:53 AM, Dave Tedeyan via RE-wrenches wrote: Hi Matt, I've used these in the past when on a comp roof and there was no good way to get into the rafters (or TJI's in this case) https://sunmodo.com/nanomount/ You might want to replace the screws with something shorter and beefier though to get more grip if you are only going into 1/2" plywood. Cheers, Dave On Wed, Mar 29, 2023 at 10:38 AM Matt Sherald via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: Hi All, I've run into a roof-mounted job where the roof is built-up with the following: Comp shingle Plywood Foam board T&G (roof deck, but also interior ceiling) The beams that hold the t&g up are wide-spaced and not convenient for fastening the full extent of the array. This being the case, I was considering other fastening options and am writing to pick the collective brain of the Wrenches to see how others have addressed similar situations. One thought I had was to use the PLP Easy Mounting Foot and I'd be glad for any opinions on that or another solution. -Matt -- Matt Sherald PIMBY Energy, LLC 304-704-5943 _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org -- [image: Logo] <https://www.sungineersolar.com/> *Dave Tedeyan, P.E.Owner | Sungineer Solar* *p: *he | him | his *a: *1653 Slaterville Rd. | Ithaca, NY 14850 *w:* www.sungineersolar.com <http://www.sungineersolar.com/> *c:* (607) 288-2898 _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. 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_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org