The player's base covers an area of 44x44 fields. 40x40 of these fields can be used to position buildings on. Each building prevents enemy players to deploy units on fields that directly surround the building. For example, the enemy player can't deploy units between two buildings that have exact two free fields between them.
Here you can find a list of all buildings and their size.
|3x3||Arena Gold Mine Gold Vault Guild Hall Heroes Altar Mana Mill Mana Vault Relic Hall Training Center Watchtower (and upgrades)|