I have two metal sheds by Yardmaster. One has external doors and the other internal doors.
The external doors are weatherproof as the track is on the outside and drains outside.
The internal doors are not weatherproof as the track drains inside and the floor gets wet, this will evaporate into the air inside the shed and cause rusting of any equipment stored in it.
So always buy sheds with external doors.
and rot the wooden floor... as mine has...
:-[