How thick should the garage floor be
I am building an unconnected carport/garage (haven't decided whether or not to close in the sides completely) - and building it myself. So even if the walls don't stand up, maybe the floor can be useful. So how thick should the floor be? It will be 16x24. Mostly it will be used just for storing the car but I do have some day dreams of putting in some heavy equipment like a metal lathe, etc. so it needs to be strong enough to hold some heavy equipment.
Thanks for any help.