[RE-wrenches] Attaching Array To or Through Ply
Ray Walters
ray at solarray.com
Fri Mar 31 19:13:37 PDT 2023
Chris, Jason, all;
I really like the idea of double clamping in serious situations. I wish
we had had this conversation about 2 months ago, before we installed 2
more systems in Puerto Rico. I definitely would have suggested the team
try that. Save it for next time, and hopefully we get a bit better with
new found idea on each install.
Thanks again for great ideas Wrenches,
Ray
On 3/31/2023 2:15 PM, Jason Szumlanski wrote:
> Hi Ray,
>
> I'm happy to have some confirmation from another major storm's impact.
> My father has a home in Dominica, which was hit by Maria with 165 mph
> winds before it moved on to PR. He had a mixed bag of results with
> solar panels (forget about the pole mounts I installed there over 20
> years ago!)
>
> I was just reminded by your email about something I plan to try. For
> panels that are pitched on flat roofs, I am going to double up and
> install BOTH IronRidge CAMO and UFOs. With proper planning, it would
> be pretty easy to install with UFOs first and then go back and snap in
> all of the CAMOs without much labor cost and an acceptable material
> cost for the added peace of mind.
>
>
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
>
>
> On Thu, Mar 30, 2023 at 9:45 PM Ray Walters via RE-wrenches
> <re-wrenches at lists.re-wrenches.org> wrote:
>
> Hi Jason;
>
> I was like you: thinking good ol' bottom mounting with SS hardware
> was the best. All of us old wrenches were wrong.
>
> The top down mounting system is much stronger. I've only had a
> handful of failures over 25 years, and all were bottom mounted.
> The module completely ripped off the rack, leaving the stainless
> hardware, washers, etc with a thin sliver of module frame
> between. For repairs, I come back and install 1/2" SS angle on
> the inside of the module frame to spread the load more. AND....on
> new installs, no more bottom mounting. If you compare today's
> modules with old 12v models from 20 years ago, you'll see: much
> thinner metal on the bottom frames now.
>
> Meanwhile I saw several systems survive Hurricane Maria in Puerto
> Rico: all top down mounting. You are correct that the failures
> come from the modules themselves letting go, not the racking.
> Either the wind itself is so strong as to blow the glass, then the
> frame looses its structure, or flying debris breaks the glass.
> There were some MW PV fields that got tore up pretty bad. So no,
> ground mounts definitely can be destroyed. They had tornadoes
> moving inside of the hurricane, and you could see it in the
> damage, 50' wide strips of total carnage with undamaged modules a
> few feet away. Like you said, The storm has a mind of its own.
>
> As far as mid clamp T bolt failures, I can confirm that probably a
> majority are not installed correctly, especially Unirac, which are
> terrible to get the T lined up right. I've done numerous
> inspections world wide, and a signifcant % of racking I looked at
> was NOT installed correctly.
> 1) The Ts not squarely lined up with the rail,
> 2) massive over torqueing, to the point the bolt can't be reversed
> 3) under torqueing, to the point the modules had slipped down a
> little.
>
> Most of these problems come from installing with an impact
> driver. Impact drivers are a great tool (so is a hammer), but you
> got to know when and where to Not use them, too. They're great
> for installing the lags and L feet, but then get that tool off the
> roof.
>
> Use an electric screw driver, socket wrench, or *drill with a
> clutch* set low to snug up the clamps, and then final torque with
> a torque wrench. Period.
>
> Ray Walters
> Remote Solar
> Former NABCEP 2004-2016
>
>
> On 3/30/2023 4:34 PM, Jason Szumlanski via RE-wrenches wrote:
>> That would be great if it were possible! I'm not sure how you
>> bottom mount a flush mount array. For a brief period many years
>> ago, I was building solar trailers. I would bottom mount 4-6
>> panel arrays on rails in my warehouse and then hoist them up and
>> through-bolt the whole array on the top of a trailer. I wasn't
>> about to allow a trailer going 80 mph on the interstate to have
>> panels mounted on the roof with mid-clamps! I had no idea what I
>> was doing, but I had enough sense to know that would have been a
>> bad idea!
>>
>> I did provide feedback to IronRidge regarding a handful of
>> failures from Hurricane Ian, but most of the issues we saw were
>> most likely related to catastrophic module failure. After all,
>> they are only tested to 5600 Pa uplift for even the best options
>> we have on the market and 2400 Pa for some (which I refuse to
>> use). The mid-clamp T-bolts tearing out of the rail are slightly
>> concerning, but this was pretty rare, and honestly it could be
>> related to installation torque issues, misalignment, or coupled
>> with module failure. There was no widespread or definitive reason
>> for rail failures at the clamp locations.
>>
>> I would suggest that FEMA's recommendation is overkill and not
>> based on much science, but conclusions based on anecdotal
>> information without statistical data. It should be scrutinized. I
>> think it would be a good idea to consider bottom mount for ground
>> racks and tilt mounts that allow it, but it's just not practical
>> or possible in the vast majority of residential installation
>> cases. On that note, I am not aware of any ground mount failures
>> around here from Hurricane Ian except for submerged arrays that
>> were washed away from storm surge (Yikes!). And the handful of
>> failures that we observed were a drop in the bucket relative to
>> the installed numbers here.
>>
>> One other thing. Wind direction, upwind obstructions/windbreaks,
>> and luck have a huge amount to do with failures (of both PV and
>> roofs themselves). These storms pick winners and losers. You will
>> have ten houses in a row with pool enclosures mangled, and one in
>> the middle that is unscathed. It's crazy to see. We have lots of
>> gated communities with houses close together. When wind
>> accelerates between houses, it can topple air conditioning units
>> and pool equipment. If you look hard enough at where the wind was
>> coming from and the surrounding area, you can really see how
>> there are so many factors that come into play.
>>
>> Jason Szumlanski
>> Principal Solar Designer | Florida Solar Design Group
>> NABCEP Certified Solar Professional (PVIP)
>> Florida State Certified Solar Contractor CVC56956
>>
>>
>> On Thu, Mar 30, 2023 at 7:35 AM Christopher Warfel via
>> RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
>>
>> If you look at FEMA's design guide for solar installations in
>> FL and the Caribbean, the recommended module to rail
>> attachment method is back to using the attachment holes in
>> the solar module. Chris
>>
>> On 3/30/2023 5:56 AM, Jason Szumlanski via RE-wrenches wrote:
>>> This thread has morphed into more than it started as, and
>>> for good reason. I want to provide some practical/anecdotal
>>> information, having just gone through arguably the most
>>> catastrophic wind event in Florida's history (Ian) since the
>>> boom in solar energy started, and another major wind event
>>> (Irrma) just 5 years ago.
>>>
>>> First, Aside from the Sunmodo and Quickbolt decking-only
>>> products, I would check out IronRidge's new entrant into the
>>> market, the IronRidge HUG. If you can't find info on it, ask
>>> your distributor or IronRidge sales rep. They have data on
>>> truss attachments and also missed truss installation
>>> procedures. It's a unique approach to a dual-purpose
>>> product, and they did a stellar job on the engineering
>>> documentation in my opinion.
>>>
>>> Ok, now let's get to my most important point. Due to
>>> Hurricane Ian, the number of roofing PV attachments that I
>>> have witnessed that failed due to fastener pull-out (mine or
>>> competitors):
>>>
>>> ZERO
>>>
>>> The only building where we had any mounts fail was on a flat
>>> roof with pitched panels and Anchor Products mounts on TPO
>>> membrane, but the mounts themselves did not cause the
>>> failure. The roofing system itself failed, causing a small
>>> section of the PV system to fail. But even in that case, the
>>> following applies...
>>>
>>> The weak point in a well-designed and installed system is
>>> not the fastener or flashing system. The module to rail
>>> connection is where we saw failures. These failures fell
>>> into a few categories:
>>>
>>> * Windborne debris struck panel, panel frame failed, panel
>>> popped out of mid-clamps.
>>> * Catastrophic wind forces popped panels out of mid-clamps
>>> (a good percentage of panels found INTACT and still
>>> functional on the ground!) I suspect the panels became
>>> covex in the wind, bending frames inward.
>>> * Windborne debris struck mounting system components,
>>> panel dislodged, often still on the roof suspended by DC
>>> leads.
>>> * Mid-clamp t-bolt tore out of aluminum rail channel
>>> (IronRidge UFO, Unirac SM).
>>> * Mid-clamp sheared off (Quick Mount QRail).
>>> * Unexplained module detachment failures.
>>>
>>> On 9/28/22, while I stayed up all night bracing myself
>>> against my front door that I thought was about to fail, I
>>> was imagining how many roof leaks my clients were about to
>>> endure, and wondered about the efficacy of my business going
>>> forward. Those fears never materialized. Aside from a
>>> handful of minor panel dislodgements, there was no panic
>>> following the storm (with respect to solar panels). The
>>> bigger problem became all of the people needing to remove
>>> panels for roof replacements, but PV panels largely
>>> protected roofs in the areas where they were installed.
>>> Sadly, the rest of the roof often did not fare as well.
>>>
>>> Anyway, back to the decking attachments. I have been
>>> skeptical of non-flashed products for comp shingle roofs for
>>> a long time. My thinking is coming around, particularly with
>>> the HUG (I trust IronRidge's testing regime). And sealants
>>> have come so far. This method will remain up for debate
>>> probably for a long time. Around here, I am pretty certain
>>> these products will outlast the shingles they are placed
>>> upon. We only get 15 years out of most shingle roofs around
>>> here.
>>>
>>> About the pull-out fears... Mine are gone. We have done many
>>> flat roofs with long fasteners through steel decking or wood
>>> decking. These screws are usually something like #15 XHD
>>> screws in lengths from 5 - 12". Not a single failure. We
>>> have also used Quick Mount QBase Low-Slope bases on pitched
>>> tile roofs that were only screwed into decking with 4
>>> fasteners each (due to horizontal truss transitions) in some
>>> cases. Zero failures. But the most relevant attachments I
>>> can think of that are germane to this discussion are the
>>> many thousands of S-5 SolarFoot that we have screwed into
>>> decking on 5V metal roofs around here. These have four
>>> screws per attachment, and S-5 load tests show something
>>> like 240 lbs of pull-out strength in OSB (adjusted for
>>> safety factor). When engineered for our wind loads, we
>>> usually get anywhere from 36-48 inch attachment spacing,
>>> sometimes 24 inches in certain roof zones. Again, not a
>>> single failure.
>>>
>>> I have more solar installations on Sanibel Island and Fort
>>> Myers Beach (Hurricane Ian Ground zero) than anyone. Many of
>>> those have decking-only attachments, S-5 clamps, flat roofs,
>>> or other attachments other than trusses. I can tell you
>>> unequivocally that I trust decking-only attachments from a
>>> pull-out strength standpoint. When properly engineered, with
>>> cautious attachment spacing, these mounts work in both OSB
>>> and plywood. Because of the inconsistencies in OSB, we
>>> always err on the side of caution, if not in the
>>> engineering, then in the installation, by installing more
>>> attachments than prescribed. But the evidence is clear. It
>>> works.
>>>
>>>
>>> Caveat to the above: I have zero experience with snow or
>>> seismic, and no experience on roofs exceeding 8:12
>>> pitch, and few above 6:12.
>>>
>>> And one more shout-out to S-5 clamps on standing seam roofs.
>>> Aside from one minor failure of the roof metal itself, not
>>> an S-5 failure, we had zero failures of S-5 clamps
>>> attachments to report.
>>>
>>> I hope this anecdotal information helps and sets some fears
>>> aside. Please reach out to me off-list if you want any
>>> specifics or details about our experience with catastrophic
>>> wind events.
>>>
>>> Sincerely,
>>>
>>> Jason Szumlanski
>>> Principal Solar Designer | Florida Solar Design Group
>>> NABCEP Certified Solar Professional (PVIP)
>>> Florida State Certified Solar Contractor CVC56956
>>>
>>>
>>> On Thu, Mar 30, 2023 at 2:47 AM William Miller via
>>> RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>> 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 <http://www.millersolar.com/>
>>>
>>> CA Lic. 773985
>>>
>>> *From:*RE-wrenches
>>> [mailto:re-wrenches-bounces at 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 at 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 <tel: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 at 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 at 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 at 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
>>>
>>>
>>>
>>> _______________________________________________
>>>
>> --
>> Christopher Warfel
>> ENTECH Engineering, Inc.
>> PO Box 871, Block Island, RI 02807
>> 401-466-8978
>> <http://entech-engineering.com>
>>
>>
>> _______________________________________________
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