Plywood subfloor; removing wall to wall in dining room, living room and 2 hallways. Problem I see is kitchen and bathroom that come off hallways have had ceramic tile put over another subfloor, so kitchen and bathroom are about 1"- 1 1/8" higher than subfloor where new hardwood or engineered will go. How can I transition. Suppose I go to 3/4 " hardwood, will I need to build up the subfloor before hardwood. What's the maximum difference.