Flooring Tile - Mixed Media Floor - Hardwood and Tile

I've seen some beautiful floors using a mix of hardwood and stone tiles. It look fairly easy to do. Basically, wood planks frame a single stone tile.

My concerns are the expansion gaps and what to fill it in with. I've heard people say use: 1) 1/8 inch cork, 2) flexible grout, 3) flexible caulk.

Another option I was thinking of was (with a floating hardwood floor installation) was to let the tiles "float" also. Which is to not adhere the tile to the subfloor but let the tile rest on the same wood foam subfloor. It would stay framed within the wood planks and this would let it "move" along with the wood floor.

Any thoughts on the above?

Tile is more rigid than wood and theres no give in it at all. If you dont set it in thinset it'll crack. Moving tile = cracked tile. Youll need to use caulk at the wood/tile transitions.

Thanks again Johnny.

Excuse my ignorance but why would a tile crack if it wasn't adhered to the subfloor? I'm thinking the hardwood expansion might just push it along the foam underlay but I can't think of a reason for a tile to crack under normal use. I thought cracking was associated with subfloor movement where the tile is pulled apart because it was attached to the subfloor going in different directions.

It'll crack from the point load above when its walked on because its not fully supported from below. Ive installed tile for a long time but never that way. Do a test. Lay out some tiles on your subfloor with the cushioned underlayment and walk on them for a few days. See what happens. I think I know the answer but Ive been wrong before.

Ah now I see what you are getting at. Ceramic tiles have a spaces underneath them.

I should have been more clear, I was thinking of using marble stone tiles. The bottoms are completely flat and level. So I should make sure the floor is completely level or install maybe a 12x12 inch cork underlayment for each tile to cushion it (since I need to step up each tile in height to match the wood floor).

If I did that, will that address your concerns?

I dont think so buy give it a try. The point I was trying to make is that when you walk on the tile you create a point load underfoot that is only in that one spot. Pressure from the top in one spot and soft underlayment will make the tile crack at that spot. Thats been my experience but hey give it a try and see. Natural stone is just as susceptable to cracking as ceramic or porcelain.