Minecraft wiki entry for Safe_home, associated text: Also, be aware that creepers can detect you and start their fuse from one block away, even if there is a low wall or fence keeping them away. Ways to avoid this are: build a wall at least two full blocks tall (even if it is made of certain translucent blocks such as slabs, fence or glass); or build your home with all spawning surfaces on all traversable paths sufficiently lit.