[RE-wrenches] truss loading

[Solar Plexus]

Hi All,

We were recently notified by our local building department that all  
future building permits will require a letter from a state licensed  
engineer stating the existing roof trusses are adequate for the  
additional load a solar system will add.  All roofs in our area have  
a 30 pound per square foot snow load requirement.  The building  
departments concern is truss manufactures design the trusses to very  
tight tolerances and there is no room for additional load.  Has  
anyone had to address similar requirements?  Any ideas on how to  
approach this issue would be appreciated.

Thanks in advance, Rip