My dad's 65 Mustang sat on gravel for 20 years, and now I swear by a $40 vapor barrier under it
I used to think a concrete slab was fine for long term parking until I pulled the tarp off his car in Toledo last spring and found rust bubbles creeping up the rocker panels from the ground moisture, so now every car in my barn gets a sheet of 6 mil plastic with a moving blanket on top, and I'm curious if anyone else has watched a floor sweat bad enough to do the same.