Hello

I would like my hardwood to butt up flush with my tile with mabay a small grout line between them. I do not want to use a t moulding and like the idea of a flush transition but do I need to be worried out the expansion and contraction then? 1 room it will be horizontal with the tile and the other will be perpendicular with the tile. Tile and hardwood will be within 1/8" height wise. Neither tile or hardwood is installed yet. Any ideas or advice?

Thanks in advance.

Which will be the 1/8" higher, tile or hardwood?

It is important that your flooring has been acclimated preferably before laying the last few boards against the tile. The wood will not expand lengthwise but it can expand with change of humidity. Glue the last rows in place so there will be less movement. I prefer to have a single board perpendicular to the flooring that dies into the tile, a one board border. I like to have a sanded caulking that will match the color of the grout to be installed between the tile and hardwood. I think most tile floor grout has sand.Some tile brands have caulking to match. You can plan in advance. I use a foam backer rod to fill in most of the gap and leave less than a quarter inch gap to be filled with the caulking.. I try to leave one half the width of the grout between the tiles.
The factory edge of the tile next to the gap is best. The wood edge ought to have a radius of an eighth inch or less so it will not splinter.
I cover the caulking with the final coat of floor finish so it looks to be the right color and is easy to keep clean. I just cut it in with a brush.

the tile

thanks for the detailed explanation. Does the foam backer rod give it some wiggle room if the hardwood does expand? Also when you say, single board perpendicular to the flooring that dies into the tile is that just like making your own t molding out of a piece of hardwood , i guess it not really a t molding then but it will be flush.

Im a DYIer and never installed hardwood before or a flush transition.

Thanks in advance again.

No T-molding necessary. A one strip of flooring next to the tile is what I mean. The foam backer rod is made to fill an area that may not be the same all along the gap. It is made with closed cell poly-ethylene foam and always stays flexible.
It comes in different diameters. You can sometimes find foam fabric type of packing material that can be rolled up and pressed into the gap making a uniform depth to be topped off with the sanded caulking. It is kind of like foam rubber, but more flexible.
The factory edge of the tile will have a rounded or chamfered edge to help meet the wood. You still need to ease the edge of the flooring so when you caulk and then finish off with your finger you will not get a cut or splinter on your finger tip.
If you would like to help the joint a little more even, you could use a strip of asphalt roofing to shim the edge of the flooring where it meets the tile. Latex adhesive can help hold the row against the tile. Don't use a solvent based adhesive with the tar paper shim.