Minecraft wiki entry for Survival_in_an_infinite_desert, associated text: In theory, a small house with 5x5 walls needs 32-34 sand for the walls, plus 25 dirt or sandstone for the roof. In practice, you can get away with less. You could use 10 blocks in a 3 x 3 pattern above the floor space (not above the walls), plus 1 block on the wall to anchor that 3 x 3 to the wall = 10 blocks. You could clip the 4 corners (but not the middle) off the 3 x 3 block and reduce it to 6 blocks, but if you go down the minimum blocks and are using sandstone, don't make a mistake! It takes a long time to break sandstone with your hands, and breaking it doesn't drop a sandstone block, the block just gets destroyed.