How thick must the floor be over the joists? Does the thickness include the floor covering (tile)?
I'm not a contractor or am I familiar with anything regarding New York but I am familiar with floor installation. I do know however that floor covering be it tile carpet or whatever does not include the thickness of the floor. I would also imagine that most building codes for floor thickness, would be at least 1/2 inch plywood over the floor joist. Also with ceramic tile,it is not recommended that it is installed on only one layer of plywood over the joist.You need 2 sheets or installed over the existing wood plus a cement board
The spacing of the joists dictates the thickness of the floor decking wood. Common is 16 in on centrs. but others will alter that. No your structrual thickness is only based on the structrual material. In your case the plywood. About 25 years ago; a common practice was a 1/2 in sub floor. then a 5/8 in underlayment over. That was dropped do to cost as well as newer floor decking products became available. Today probably 99% construction is a 3/4 in. tongue and groove, some call sturdy floor applied to 16 in on centrs. Plywood products have stamps on them that indicate floor joist spacing and roof rafter spacing. The smaller number would be for the floor spacing.
