[RE-wrenches] Module Racking Attachment to SIP Roof

[Bill Hoffer]

Gary

Has anyone checked with the SIP manufacturer, this is a laminated structure
and will have more holding power than simple sheathing between rafters
(which is still doable with larger mounting plates and multiply short
screws).  It could be that they have performed shear and pull out tests when
mounting directly to the sheathing.  SIP's are engineered and you should be
able to find engineering data to justify a mounting system.  The bolt
through with steel plates on both sides sounds like overkill to me, even if
the pull out was less than needed doubling up or tripling up screwed plates
on the surface  designed for holding into sheathing seems the better
solution, a lot less labor in the long run.

Bill

On Tue, Jul 26, 2011 at 11:48 AM, R Ray Walters <ray at solarray.com> wrote:

> One problem that came up on a project recently, is that your penetrations
> (as proposed in your solution below) will essentially ruin the thermal
> performance of the SIPs system.
> The whole point of the SIPs system is that there are no thermal short
> circuits  such as framing members that allow heat to be transmitted around
> all that insulation.
> The project I was referring to was with NREL, and a smart engineer caught
> it, and forced the PV contractor to mount in a way without penetrations.
> I also work with very savvy architects that are now specifying minimal
> penetrations through the thermal envelope.
> I'd suggest a standing seam roof, with S5 clamps. Ask the roofer to use
> extra attachment screws, if you're worried.
>
>
> R. Walters
> ray at solarray.com
> Solar Engineer
>
>
>
>
>
> One solution could be a product that had a bolt-plate on the bottom of the
> SIP, that penetrates the SIP with long 5/16" threaded bolt(s), and then
> attaching to the PV mount at the top of the SIP. The UniRac SolarMount steel
> flat-top mount has four 5/16" bolt-holes and might be a good choice. This
> method should have no problem achieving the required pull-out resistance.
>
> Any suggestions, installation experience, on how to put PV on a SIP roof?
>
>  --
>
> Regards,
>
>
> Gary Willett, PE
>
>
>
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-- 
Bill Hoffer PE
NABCEP Certified Solar PV Installer™
Sunergy Engineering Services PLLC
2504 Columbia Ave NW
East Wenatchee WA 98802-3941
SunEngSer at gmail.com Cell:(509)679-6165
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