A common misconception about tile and grout is that grout will somehow assist in stabilizing a tile installation. It does not. Unless you use epoxy grout it will add no significant structural elements at all.
So why should I use grout?
Grout is, structurally speaking typing, simply there to fill the spaces between tiles. That is an oversimplification, but it describes the grout’s function. More to the point, it is there to keep other things out of that space. Without grout the possibility of dirt, grime and all sorts of unruly, unwanted things may collect in the spaces between tiles. This may lead to not only unhealthy conditions, but also the chance of damaging your tile while trying to remove those things.
Does epoxy grout help stabilize tile?
If you’ve read any of my other posts regarding grout you have more than likely seen me state that epoxy is different. This subject is no exception.
Epoxy grout will actually add to the stability of your tile installation – to an extent. Epoxy will stabilize only the area between the tiles – the grout lines. It does not stabilize your tile enough to replace proper installation methods. This is not what epoxy grout is intended for.
A couple of reasons for using epoxy grout include the durability, ease of cleaning, and its ability to withstand staining. It is not intended as a product to make a sub-par installation correct.
How does epoxy help?
To the extent that it does stabilize your tile, it will only do so in the direction of the plane. If you think about tile on a floor epoxy grout will not (to any significant amount) stabilize your tile up and down. If you have a corner of your tile that does not have support beneath it, the tile will still crack eventually. It will take a bit longer because of the epoxy, but it will still crack.
If you have two tiles (not installed on anything) that are held together by epoxy grout between them you can grab each end and bust them over your knee like you would bust a baseball bat (if you were insane) and they would break apart. You can not pull them away from each other and pull them apart – ever. That is the direction of the plane.
So although epoxy grout does add some stabilizing features to your tile installation it should not be used in that capacity.
Grout is an integral part of a correct tile installation but not in a structural way. As you plan your installation keep that in mind and treat your grout simply as an aesthetic part of your overall project. It will not assist in stabilizing any part of your tile. You should only be concerned about the color.