The ARROW type metal sheds have a propensity to 'sweat' from the ceiling too. I bolted two of them together to provide the needed length, but also had an expensive 'all weather' cover on the car, so no damage to the car occurred. However, with the salty-air marine layer coming in almost nightly, aluminum bits on some of my motorcycles didn't fare well
Not sure if installing 1" thick hard foam sheets on the ceiling will cure the problem, maybe someone who's done it will chime in