Hello, I live in Austin Texas. My house currently has a 8' X 12' cement patio that is attached to the house on one side. We would like to expand our patio to 11' x 22 feet. My current plan is to pour a 6 inch slab tieing into the existing patio with an expansion joint on each side of the open patio. Once the Slab is set, we plan to lay flagstone over the entire top side of the 11' x 22' of patio. I will use a wire mesh 3 inches of the middle of the new pour. As well, I will pour the new slab in 3 pours. I am just curious if I am overlooking anything.

You should look to see how deep the earth was removed under the old slab. Try to match that with gravel fill so both the old and new will have the same base.