I did a search but couldn't come up with a solution to a potential problem. I'm installing 3/4" thick 2-1/4" wide red oak (unfinished) in an area that is 11' x 19'. Both ends have 3/8 " cement board down for tile after hardwood Is complete. There is 12' between the cement board. What is the best way to deal with expansion between the two cement board areas? Hardwood will be parallel to cement board and will be installed now. I am I'm upstate NY. Thx in advance for any help.

Depending on the relative heights of the hardwood and tile, use a reducer or transition piece. If you have the tools (table saw and router) you could make these yourself or buy them.

Heights will be very close to the same. What type of piece do I create without it being a trip hazard?

I would use a metal edge for the tile and either but it tight with the wood or leave a s

Rule of thumb calls for an expansion gap. If the heights are identical or nearly so then use the transition molding. If not 100% identical you could shave down the underside of the side of the T molding that sits on the higher surface....depends how much of a tilt without doing the shaving. T molding should be at least 1/2" thick. I have made mine from a piece of the same 3/4" thick flooring. I put a 15 degree chamfer on each edge so that the molding has a ramp effect toward each floor surface. The edge of each chamfer is 1/4+" thick. It's readily available if you just want to buy it...I have seen it at Home Depot and Lumber Liquidators. Also, if you buy it you'll be able to get longer lengths than what you can make yourself from pieces of your flooring.

Why hardwood before tile? It's always the opposite.

There is an exterior door at each end of the room. Tile at each door with hardwood in between.

Thanks to everyone for the help.

No I always suggest hardwood first because you can adjust the height of tile.

I am doing hardwood first, but have installed cement board prior so I had an outline to work with.

Just thinking about it...it seems to make more sense to install the tile first as it would be easier to make adjustments to wood, e.g ripping the boards to needed width or angle, than having to adjust the tile.