Minecraft wiki entry for Elevators, associated text: Starting at the bottom the entrance to the shaft should be in a wall that is at least one block thick. The entrance should be a 2 block high opening with a door set in the last blocks space before the two deep space for the elevator. The door is to keep the bottom two water sources from leaking out the opening. Now, step into the shaft and place signs in a zigzag up one of the 2 block wide walls as high as you can reach. Then, fill in the gaps between signs with water sources, thus forming a zigzag of water blocks. Reload on water buckets and ride the elevator up as high as you can, place more signs as you bob up and down in the topwater block, and then place more sources. Repeat till you reach the top.