Hi, I'm currently preparing a base for a new concrete slab patio. A portion of the area has an old piece of concrete acting as a path around the house and it has a heavy slope on it. The slab I intend to pour will be 100mm thick so I need to level up the area of old concrete too. My question is should I remove this old concrete first or just throw down the 804 and compact it on top. On the very right by the house is 4inches so I don't need any gravel there but I need up to 3 inches back to where it meets the gravel on the left. See pic: https://photos.google.com/share/AF1...?key=QWNwVmUwaktQU2FhT2xJVFZhYV9DOGVkaTlQQV9R Thanks