Like the patio below, the hillside was excavated, and a gravel base installed. Each step will rest partially on compacted gravel and partially on the previous step. Because using the forks could damage the stair underneath, the lift gently sets the stones into place with a nylon strap and chain harness. After the tread is in place, Roger checks it with a 4-foot level. Each one has to be perfect, or it will throw off the entire stairway.