How to add on to a concrete patio?
Great question. Adding this addition requires a really good, deep, compacted base. I would isolate it from the building by 1/2 inch, but if the base is good, rebar to the existing pad will help stop any displacement. You have to expect some settling, but the better the base, the smaller the amount. Web rebar won't help much, but 3/8 or 1/2 inch bar will hold the joint. The trick will be compact, wet, compact, wet. Make it rock hard. Good luck.