[RE-wrenches] PV wind load

[Patrick Redgate]

Call unirac; find a structural engineer who is green in the good sense  
(not cents); get specs from the truss manufacturer; speak with his boss.

Sent from my iPhone

On Dec 4, 2009, at 5:55 PM, Rebecca Lundberg <Rebecca.Lundberg at powerfullygreen.com 
 > wrote:

> Solar is somewhat 'new technology' where I live. :-) I have a  
> building inspector that feels that (32) Sanyo modules (6.88 kW  
> array) mounted to a house roof is going to cause undue stress to the  
> roof truss (it is a regular house in a Minnesota suburb, building  
> height is 26', 30 degree roof angle, in a suburban neighborhood. 2"  
> x 4" manufactured truss). We are leaving 12-24" on each edge with no  
> PV, and are careful to attach to the center of each rafter.
>
> The inspector is not that concerned with dead load, but is  
> especially concerned with wind load. We have provided an engineering  
> letter that ascertains that a solar array mounted parallel to the  
> roof surface is well within the parameters of what a typical roof  
> truss can handle. We were required to have an engineer look at this  
> address specifically, so we then provided an additional engineer's  
> letter that affirmed that yes, solar mounted in the manner we  
> proposed (with Quick-Mount attachment and Unirac SolarMount rails,  
> all installed according to manufacturers' instructions) would be  
> fine on this home. The building inspector insists that the wind load  
> is excessive, and wants more analysis. Do any of you have ideas,  
> experience, or data that might help me?
>
> Rebecca Lundberg
> Powerfully Green
> Champlin, MN
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