"Walls are great for keeping your village safe and your enemies in the line of fire."
Walls are structures that obscure the path of enemy ground troops, with an identical function to that of Walls in the Home Village.
Just like in the Home Village, Walls can be bypassed completely by air troops (Beta Minions, Baby Dragons, etc.), and also do not count towards destruction percentage when destroyed.
Walls in the Builder Base come in segments of five. These segments cannot be separated but can be rotated. When upgraded, all the walls in the same segment will be upgraded at the same time.
This is true when counting walls. When you unlock new walls, it may say that you unlocked 25 walls, but there are only 5 more wall segments.
Walls can be circumvented by destroying them or positioning ranged troops to shoot over the walls. Walls can be bypassed completely by air units such as Beta Minions.
Melee units will only attack walls if there are no other buildings near them and if there is a building on the other side of the wall.
Ranged units will only attack walls if there are no other buildings in their sight ranges other than those across the wall that is (almost) completely surrounded by walls and that are outside its attack range.
Bombers deal additional damage to Walls, much like Wall Breakers. However, their damage bonus is not as great as those of the Wall Breakers but it is high enough to destroy Walls in a few attacks.
The Bomber's Big Bomb ability allows it to deal heavier damage to walls.
Purposely create gaps in walls to put a trap in as the enemy troops will walk into the gap instead of breaking the wall.
You can also do this by putting a Crusher in the gap.
Use walls to surround defenses to protect them. Try to surround structures that assist in defense so they do not get taken out easily.
It is unnecessary to protect resource buildings with walls as you do not lose loot on defense; you can only gain loot bonus from attacks.
However, storage buildings have high hitpoints and putting them near defensive buildings inside the walls can protect defensive structures and give them more time to take out enemy troops.