Here the "moveable buildings" are pretty much not taxed. Things on skids etc. If you put a foundation under them or even put them on piers, then they are taxed. A pole barn doesn't need a building permit, it is doesn't have a foundation, but can be taxed after being built. There are so many different rules in every different county and town/city. You have to check with your tax assessor to see what the existing rules are at the time. Then if they change the rules, you can often be "grandfathered " in for tax purposes.