I just obtained a shed that will be my new workshop. It is 16x20 with 2x10 joists underneath and 1/2" plywood floor. It came pre-assembled (it was a display unit and the dealer was moving so I got it for a great price) so I was unable to insulate before it was fastened to the foundation. I'm wondering what would be the best way to insulate the floor? I see two options. The easiest would be to lay down 1" ISO sheets on the existing plywood floor and cover with 1/2" plywood or OSB. The drawbacks are that it only has 1" of insulation and I'll lose about 1 1/2" of interior height. The second option is to crawl underneath the shed and install 2-3" of ISO between the joists. This would offer me more insulation but will be a real pain in the butt to crawl underneath to install the insulation. I live in Northern Virginia and it can be very humid here, so that's a concern as well. Is there anything else that I should be considering? Last piece of information, I'm hoping to run electricity to it in 6 months to a year and then install a room-type air conditioner and dehumidifier.