墙是可以被建造，可以被破坏并且可以用來阻挡玩家和怪物的行动的建筑单位。草墙、木墙、石墙和铥矿墙分別擁有100，200，400 和800 的最大生命值。和流行的看法不同，在海岸边建造墙并不能起到限制行动的作用。
Likewise using cut stone is a loss versus using another piece of stone wall. In addition, the cost to fully repair a completely destroyed wall is much higher than just breaking the wall down with a hammer, and starting fresh. Once they are broken down completely it can take eight or nine pieces of wall to completely build back up to a top level wall, due to the way the repair function works.
The Thulecite Wall is the toughest of the walls, having 400 health when initially placed and a maximum health of 800 when fully upgraded. It can be crafted using an Ancient Pseudoscience Station at the cost of one Thulecite. When broken down with a Hammer, it will yield Thulecite Fragments.A Thulecite Wall can be placed down to block the path of both creatures and the player. When built and placed, it will be at its third tier of repair. It can be upgraded into two more tiers with Thulecite Fragments or Thulecite. When hammered, the fifth tier will yield two Thulecite fragments, while the other tiers will only give one. This means that if the player doesn't repair a third tier wall and it gets damaged, it's better to hammer it down and replace it rather than repair it. Thulecite Walls are also found naturally in the Ruins, sometimes around Ancient Guardians and Damaged Clockworks.
- Before they were implemented, Thulecite Walls had a grayish color instead of the current golden one.
- Since Thulecite Walls only take one Thulecite to build and each wall drops Thulecite Fragments when hammered, the player can make the walls, hammer them down when they get useless and still craft the original Thulecite back as long as they place the walls separately and don't combine any of them. This also applies to stone walls, but only in multiples of six (6 stone is required to craft 6 stone walls).
- The first three kinds of walls could be a reference to "The Three Little Pigs". The pigs in the story each had a house made of either straw (hay wall), sticks (wood wall), or bricks (stone wall). The presence of Hounds being an enemy where walls are important to have could also be a reference to The Three Little Pigs.
- Prior to the Moderately Friendly Update, walls could be repaired using healing items, such as the Honey Poultice.
- Maxwell's quote for walls being held in the inventory points out how illogical it is to be able to store large wall pieces in his pocket.