Minecraft wiki entry for Safe_home, associated text: Zombies are the simplest mob to defend against. With limited mobility and no ranged attacks, walls or pits will be enough to keep them at bay. However, zombies can break down wooden doors to reach you if you're in Hard difficulty. If you're in Hard, you can make a piston door so that zombies cannot get through, or you may make an iron door. Zombies very strongly prefer to smash the top half of a door, but can't jump and smash a door at the same time (jumping resets their progress smashing the door), so putting a 1-deep hole in front of your door should prevent zombies from breaking down the door while still allowing mobs (such as yourself) to enter when the door is open. To prevent other mobs from using the entrance put a two high pillar of sand above the door, though this won't stop or even hurt the offending zombie. A way to prevent zombies from breaking your doors is to put the doors in sideways, rendering them "open" when you close them. Or you could make an iron door with a button on each side. Zombies can break down wooden doors and not iron doors. Zombies will not jump over gaps, so you can use lava trenches. If you are starting/low on Iron, you can use a fence gate or place the Wooden door parallel to either side of the doorway (when you close the door, zombies will think it is open).