I have a 14 x 14 wood single slope patio cover that I would like replaced with a hip roof. I have an issue with the patio. If you walk out my back door you step onto a 3 x 3 slab connected to the house. Then the remain 11 feet down on each side is pavestones. There is however more concrete slab to the left and right of the pavestones to make the square patio. My question is can I pour a concrete slab on top of the pre-existing slabs if I remove the pavestones to make a solid 14 x 14 slab. I have 5 inches height to the door edge.