When Bondor Solarspan or Insuroof has been selected, LLD will show the allowable span for
Wind Classification Single Span
Wind Pressure Single Span
Wind Pressure Double Span
For the selected roof sheet, LLD will use the optimum single span. If this span is not suitable for the frame width, LLD will add a purlin and use the double span data.
If LLD inserts multiple purlins, you will need to change your roof sheet to accommodate double or single span. Alternatively, adjust your design to accommodate the min/max span for your selected panel type.
LLD cannot provide Engineering for multispan.