help...tiling over hardwood

m0nguse

My step-dad installed ceramic tile about ten years ago in my home that I purchased from my parents. I just tore out the carpet and one of the tiles popped loose. I removed the tile and the thinset was very thin and flakey...the tiles didn't bond at all, I'm surprised that the tile has stayed down to be honest. He had tiled directly over the finished hardwood (real hardwood from 1959). He didn't use a plywood base or durock, just laid the tile right ontop of the wood; my hardwood floor goes right up to the door.

My question is...if the hardwood can't be refinished where the tile is now, due to moisture damage from the thinset, how do I re-tile the area? I am thinking, cutout the hardwood where I'm planning tile and install a base that doesn't flexor expand like the hardwood planking does. This would most likely entale installing 5/8" plywood and then a cement board, then tile?