Any vegetation in the path of the patio must be removed. Roger uses a skid-steer loader to clear the site, then excavates 8 inches of loamy soil. The 4-inch-thick stone slabs will sit on a base of 4 inches of free-draining gravel. Lighter, thinner slabs, such as bluestone, often require a base of stone dust mixed with cement to set them firmly in place. "These aren't going anywhere," Roger says.