I agree that you can get impressive pull-out resistance from fasteners in plywood decking only. Two brands that publish pull-out values are OMG/Drill-Tec and Blazer. The #15 OMG screws are what we lean toward.
John Mansville also has a "High Load Fastener," but I think it's just a rebranded OMG. It comes in #14, #15, and even #21. They have published pull-out values that are really high. If you use a base plate with 4 fasteners with a 3x safety factor, you still get enormous pull-out values. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 On Thu, Oct 26, 2023 at 2:06 PM August Goers via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > Hi James, > > I haven't had an application exactly as you describe with a tile roof / > plywood deck over metal trusses. However, we have installed systems with > metal roof support structures many times. Metal self-drilling screws have > impressive pullouts, so you might be able to use them with any sort of > mount that you want that works with the tiles you have on site. We have > used ELCO screws in the past, and they are now part of the DeWalt brands, > but here is an example: > > https://anchors.dewalt.com/anchors/products/screw-fasteners/ > > and a Drill-Flex example: > > > https://anchors.dewalt.com/anchors/_documents/uploads/DWANF_DrilFlex-TP-EN-rA_DDS1.pdf?1698346503 > > Some of these fasteners are completely self drilling while others require > a pilot hole. > > Best, > > August > Luminalt > > > On Thu, Oct 26, 2023 at 10:17 AM James Rudolph via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > >> Mahalo for your response Sam. That makes me feel a little better. >> >> >> James B. Rudolph >> >> >> Independent Energy >> >> C-39784 ES #10816 >> >> NABCEP Certified PV Installer since 2009 #091209-155 >> >> C. 808.313.9701 >> >> >> >> >> >> >> >> >> >> >> >> >> >> On Thu, Oct 26, 2023 at 6:08 AM Sam Haraldson <s...@onsiteenergyinc.com> >> wrote: >> >>> James, >>> >>> I can think of one install I performed in 2017 that was a metal roof >>> over metal purlins and we opted to through-bolt the entire array using one >>> installer on a ladder inside and another on the roof. We employed butyl >>> mastic and large fender washers to attach a strut frame to the roof, and >>> then we installed traditional L-feet and rails atop the strut. I have zero >>> experience working with tile so I don't know what your best methodology is >>> there but I can attest that the through-bolting has held up well at that >>> site the past five years. >>> >>> Sincerely, >>> Sam Haraldson >>> >>> [image: OnSite Energy] >>> <https://www.google.com/url?q=https://onsiteenergyinc.com/&source=gmail-html&ust=1677085494759000&usg=AOvVaw2NN36GoM1sjnS4RdC8Svt-> >>> >>> SAM HARALDSON >>> Field Operations Director >>> (406) 551-6135 >>> 1515 N. Rouse Ave Bozeman, MT 59715 >>> Locally owned and operated since 2012 >>> [image: B Corporation] >>> <https://www.google.com/url?q=https://onsiteenergyinc.com/bcorp&source=gmail-html&ust=1677085494759000&usg=AOvVaw0EluC1lXtz2KlRFag-htKe> >>> >> _______________________________________________ >> 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 >> >> _______________________________________________ > 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 > >
_______________________________________________ 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