The Roof Structure shall be modeled along with the process floors to get the reactions of roof due to Dead Load, Live Load, Wind Load and Seismic Loads.
 
The Loads for the design shall be taken from IS 875 (Part 1 to Part3) and IS 1893.
 
DL                            : 50 Kg/Sqm
LL                             : 75 kg/Sqm
Basic Wind Speed      : 44 m/s
WL                            : As per IS 875 part 3 - 1987
EL                             : As per IS 1893 - 2002 (zone -2)

Please take this into consideration and revert back with your details.
We understand that roof is in our scope but while preparing the total structural calculations this has to be considered by your good self as per the requirements mentioned above.
We shall confirm once we receive the information on that basis.
Please revert back on priority.