I have my hives on cinder blocks..and also pallets. Yes ants can be a problem...cinnamon like reccomended by Rein is a good way and ant traps placed around are helpful. But that is just another hastle I let go unless it becomes really bad. But if your hive is cealed pretty well and hive has enough stores and is healthy it would take a lot of ants to ruin the hive. But better be safe than sorry.
