[RE-wrenches] Metal Truss Roofs

[Jason Szumlanski]

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 at 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 at 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 <sam at 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>
>>>
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