We had an issue with roofing screws backing out on a commercial project many years ago. When we showed up to do the site evaluation, we noticed that there was a gap between the standing seam metal roofing and the 1/2" plywood roof decking of almost 1/4". We consulted our engineer about that issue before we installed solar, and he mentioned that roofing screws can back out if the roof decking is wet when the roofer installs the metal roofing. His explanation was that the wet roof decking dries out, and the screw head pulls away from the standing seam tab. This small gap allows the contraction and expansion of the metal roofing to slowly back the screw out of the roof decking material. This likely isn't what happened in your case, but it's worth keeping in mind when looking at new projects. We called the roofing company, and they came out and fixed the issue under warranty.
Vince McClellan President NABCEP PV Professional p: 541-485-8122 a: 860 Conger St. Suite 12,. Eugene, OR 97402 e: [email protected] w: SolarEnergyDesign.com CCB# 161672 If you have received this email and are not the intended recipient, please delete this email. Copying or using any part, content, or attachment of this email is strictly prohibited. On Sat, Sep 26, 2026 at 11:45 AM Jay <[email protected]> wrote: > My take from listening to roofers is metal over 1/2” OSB, pull out of the > fasteners is common. Just too much stress during temperature > expansion/contraction over time. > If the fasteners go into a rafter or thicker perlin then they usually > don’t pull out. > > Larger diameter fasteners does help. > And yeah just like solar companies installing feet with an impact on > setting 3, to many are probably stripped or really close being stripped > out. > I wonder if more fasteners would help the situation but then more holes > and potential leaks. > > I prefer standing seam with hidden fasteners. > > Jay > > On Sep 26, 2026, at 10:10 AM, Dana Orzel <[email protected]> wrote: > > > Sent from my iPad > > On Sep 25, 2026, at 9:54 PM, William Miller <[email protected]> > wrote: > > > Tyrone: > > Thank you for your reply. > > Upon reflection I realized this roof is one of the very few, or the only > roof, we have installed on with metal over wood. In most cases it’s metal > over metal purlins. Maybe this is why I have had no previous experience > with this problem. Does this correlate to your experience? > > By the way this location is at a low altitude with a very mild climate. > > Thank you again. > > William Miller > Miller Solar.com > 805-438-5600 <(805)%20438-5600> > www.millersolar.com > > On Fri, Sep 25, 2026 at 12:16 PM Tyrone Houck <[email protected]> > wrote: > >> Yep. Delta Rib/trapezoidal roofing with exposed screws is notorious for >> screws slowly backing out over time and progressing into rot spots and >> leaks especially at higher altitudes with seasonal snow/freeze and warm >> summers. My guess is your attachments are less likely to be the issue than >> the roof fasteners. Best of luck in your investigation! >> >> >> >> >> On Fri, Sep 25, 2026, 11:35 AM William Miller <[email protected]> >> wrote: >> >>> Colleagues: >>> >>> >>> >>> I have a long-time PV client with a metal roof. This is the type of >>> roofing with trapezoidal ridges every 12 inches. Over the years we have >>> installed three phases of solar on this roofing. We original caulked DPW >>> feet onto the roof with fasteners into the framing. Later we used DPW >>> EZ-feet with the included butyl tape. >>> >>> >>> >>> The client informed me that have had minor roof leaks due to failure of >>> the fasteners. To quote: “Unfortunately I chose the less expensive version >>> of the roofing, way back then. It has “exposed fasteners”, the screws and >>> washers are working loose.” (No one has claimed our attachments are >>> leaking but you can bet I will be looking at them closely.) >>> >>> >>> >>> This is the first time I have ever heard of this type of failure. Have >>> any of you experienced this? Can you offer any explanation on what caused >>> this and how you dealt with it? I would be very grateful. >>> >>> >>> >>> It seems to me that replacing the fasteners would invite stripping of >>> the threading into the wood sheeting. >>> >>> >>> >>> Thanks in advance, >>> >>> >>> >>> William >>> >>> >>> >>> William Miller >>> >>> Miller Solar >>> >>> www.millersolar.com >>> >>> CA License C-10 77398 >>> >>> >>> _______________________________________________ >>> List sponsored by Redwood Alliance >>> >>> Pay optional member dues here: http://re-wrenches.org >>> >>> List Address: [email protected] >>> >>> Change listserver email address & settings: >>> >>> https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ >>> >>> There are two list archives for searching. 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When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > https://lists.re-wrenches.org/pipermail/re-wrenches_lists.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: [email protected] > > Change listserver email address & settings: > > https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > https://lists.re-wrenches.org/pipermail/re-wrenches_lists.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 >
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