[RE-wrenches] No underside access metal building attachment

[Kirpal Khalsa]

Lars,
We looked into this and found some "threaded pop rivets" they were
stainless steel and you had to buy the tool and then you just drill from
the top, insert the pop rivet that leaves a threaded shaft facing skyward
that you could attach L feet or other attachments to with a nut and
washer....they guaranteed a waterproof connection and i imagine that you
could always add some Eternabond double sided butyl tape to the bottoms of
your L feet to double ensure the waterproof seal.  They supplied
engineering pullout documentation...you will need to provide them with the
thickness of the purlins, the thickness of the metal roofing, and the
thickness of the insulation if present for them to spec the right size
rivet.

The company we found that had what seemed like it would work well was
Bollhoff - a German company.  They have US distribution so you can source
the tool and materials domestically....
Good luck....

-- 
Sunny Regards,
Kirpal Khalsa
NABCEP Certified Solar PV Installer
Renewable Energy Systems
www.oregonsolarworks.com
541-218-0201 m
541-592-3958 o


On Thu, Mar 15, 2012 at 9:40 AM, Allan Sindelar <
allan at positiveenergysolar.com> wrote:

> **
> Lars,
> This has been addressed before on this list, but its been awhile. #14
> self-tapping ("Tek") screws have phenomenal pull-out strength in standard
> steel purlins. My advice is to research this through your fastener
> supplier; I have seen charts on pull-out strength of various sizes and
> materials. I think you'll find that you can come up with a screw attachment
> schedule with which you'll be satisfied.
> Allan
>
>  *Allan Sindelar*
> *Allan at positiveenergysolar.com* <Allan at positiveenergysolar.com>
> NABCEP Certified Photovoltaic Installer
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> *****************
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>
> On 3/15/2012 10:26 AM, lars Ortegren wrote:
>
>  Wrenches,****
>
> We have a project coming up where we are installing a large array on a low
> slope metal building with metal purlins. Typically we would through bolt
> our attachment to the purlins, but in this case the building is a
> self-storage, and access is not an option. Does anyone out there have
> experience with any top side only metal-metal attachments? I’ve thought
> about using some larger sized stainless self-tapping screws, but I worry
> about the pull out strength (as the roof combined with the c-channel
> purlins are only about 1/8”) and the effects of heat and cooling of the
> roof backing the screws out over time. Any thoughts ?****
>
> ** **
>
> *Lars Ortegren*
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