I have a aggregate concrete patio. I am wondering if I can build my concrete base adjacent to my aggregate patio, thus the oven base would be built on 2/3 of the new base, and 1/3 onto the existing patio? The aggregate seems secure (6" thick). I thought maybe drilling holes in the side of the patio, adding rebar that would extend into the new pour area to "bind" them together in case of settling? I'm installing a Casa2g110.