Your hardwood flooring supplier should have many types of transition mouldings that match up with your hardwood. Even if you fir up the tiled areas to plane in with the hardwood, your still going to need a transition moulding seperating the two floors. Unless you have a honkin' big kitchen, dining, foyer areas, 5k sounds like you are being gouged big time, imo to lay down some plywood.

My transition from hardwood to tile looks just like Sherrilea's. No special moulddings. We did recently replace the tile and the new porcelain tile was much thinner than the old thick spanish-style tile that we ripped up. The tile installer used some type of cement to raise the floor to match the hardwood height. The section that has tile is on a slab.

How can there be a 3/4"difference? Your subfloor starts level in these two areas. Your hardwood is 3/4". For tiled areas, you have some type of hardibacker board (1/4 usually),then mortar, then your tile is 1/4" or 3/8". They should be equal or very close. I'd be nervous about the contractor if he is somehow getting an extra 3/4 inch under the tile. Even if he used thicker hardibacker it would only be 1/8" different or so.

Thanks everyone for your comments.

I didn't really understand where he was coming from when we had this discussion initially then out of the blue yesterday we get a change order request with this as a line item.

Right now everything is even and we haven't picked any of the flooring options (the hardwood or tiles) and he is already asking for the cost to add additional plywood.

5K sounded absurd to me to put down an extra layer of plywood. The total surface area is 4K sq feet that's a 1.25 a sq foot for plywood!!!

It depends on the layout whether transition mouldings are needed. In the above posters hardwood to tile it's at an opening with the hardwood running with the opening and looks nice without moulding, but in open areas where there are large runs butting up to the two different floorings, transition mouldings are used when the hardwood is perpindicular or even at angles one to the other. The op has large areas kitchen, dining, foyer where depending on layout, more than likely would need mouldings where the two meet when perpindicular. An alternative to transitions is running a band of hardwood matching the flooring with the tile but perpindicular to the hardwood runs. Tha takes woodworking,(milling), that some installers wouldn't make time for.