minimums should be 16 ft wide inside the building with a 12wide x 14tall door....
its preferable to have an inside space that is 10ft longer than the longest unit that will ever be stored in it, and at a minimum, 3 foot longer
a 10ft wide door is a bit tight for the new wide body units and mirrors, and anything less than a 14ft tall door and you may regret it later if you get a bigger/taller RV..
and if the inside parking space is too small, you wont be able to walk around the unit for service work and upgrades when its in the building.... which means it could just as well be stored outside under a wrapper/rv cover(if thats where you have to move it to be able to work on it anyway).... and if you have extra space in the building, a nice toolbox and assorted power tools will take up some of the space....
