UniRac [RE-wrenches]

[Kurt Nelson, SunWise]

Doug Pratt wrote:
> 
> For folks who are concerned about getting to the roof to reshingle or whatever, I usually recommend installing "sleepers".  
> 1.Lag a 3/4" threaded-pipe floor flange substantially into a rafter.

Hey Doug,

I think we need to introduce array size and wind load to this
discussion.  I have seen snow build up behind a roof mount array that
should have been calculated into the spec's of the roof design, but for
the most part it seems like wind load is the bigger concern.  I think we
need to be sure those following this discussion understand that any
mounting method has, by its very nature, design limitations, and that
any roof mount array exceeding xm2 (not willing to put that figure out
there) can not be considered under "pipe flang" nor my own "through
bolt" methods.  When I first got into solar, I never realized just what
a big deal sticking them PV's up there is!  This lack of knowledge is
also true of most "leads" and interested customers.  They don't have a
clue about the expense and considerations of the array's placement and
mounting.  

Then again, some times I just lean em up against the south side of the
house and leave the cover boxes hanging open.  That way you can wire em
in and not necessarily initate the warrantee period!  

Wait.  A few leaks aside, if a home with a roof mounted array has it's
roof blown off (really happens in hurrican, down-burst and tornado
situations), could the PV installer be held responsible for exceeding
the design limitations of the roof as originally installed? Yup.

Kurt Nelson

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