Minecraft wiki entry for Survival_in_an_infinite_desert, associated text: If you dig rather than build, you can collect most of the sand you need for a sandstone-roofed house. On the other hand, the fastest way to create a defensive barrier is to dig a one block deep trench in the sand, and use the sand collected to build a one block high wall on the inside edge (house side) of the trench, creating a 2 block high vertical obstacle that only spiders and flying or teleporting mobs can cross.