add panels on roof, does it add wind load to roof structure members?

[johndeng]

MWFRS wind load for flat/monoslope roof is only uplift load, no downward load. so we don't add wind load for joist/girder design.
But when we add tilted panels on half of the roof, panels will take uplift and downward wind load, most time downward wind load is over 20psf and uplift is only 15psf. do we need to add panel downward wind load to roof stuctural members, when we check the roof joist/girders?
Or we don't need to, since joists/girders are not roof c/c.

Thanks

 

[SkiisAndBikes]

I would recommend you contact the solar racking company. Many of them have wind/snow design criteria specific to their system compiled by engineering consultants (RWDI, etc... ) and based upon test data. Very handy, allows you to design based upon relatively specific criteria and allows for an efficient design.