We've added a small half bath to an addition, and we're planning to tile the floor ourselves even though we have never done it. The room is about 20 square feet and I'm planning 12" x 24" tiles, so 10 tiles total--how hard can that be? I know, probably much harder than I realize. Some questions:

1) Transition: The subfloor is OSB. We are planning to put down 1/8 inch Ditra (orange) underlayment, then 3/8 inch tiles. The tile will end up being between 1/16 and 1/8 inch higher than the adjoining bamboo floor depending on the thinset thickness. I would like to avoid a heavy marble or wood T threshold if possible for such a small gap. Could I use one of those Schluter metal vertical strips? If I do this, how can I be sure what height to get when the thinset thickness is hard to predict?

2) Leveling: I have read that I should get some sort of leveling system to make sure the large tiles lie flat, but they are awfully expensive--$80 or more for various components that I will use once for this small room. Any advice about how best to level the tiles?

3) Grout: Is stain-free grout best for floor tile? I have read that it can be much harder to work with and to clean off the tile as you're grouting.

  • How thick is the OSB? What is the joist spacing? How big are the joists? You need a very rigid sub-floor for tiling. My Victorian bedroom-turned-bathroom had 3/4" floorboards or chipboard, then the tilers attached 1/2" plywood on top. Nov 6, 2019 at 11:20

2 Answers 2


You need to get the schluter profile with the same thickness as your tiles. you don't need to account for the thinset because you will press the profile down on the thinset just like the tile.

That said, the T moulding has advantages. First, it hides imperfections. If you have several tiles at the transitions, it is very difficult to cut them to make a perfect straight line. Second if your bamboo flooring shrinks and expands, you need to leave a small Gap at the transition which can be covered by the T

  • 1
    Your question did not ask about adequate subfloor, OSB is not adequate subfloor for tile, typically you put down a layer of cement board to ensure that the floor has no or little flex to it. If your floor flexes you could end up having grout lines that break or even tiles that break.
    – Alaska Man
    Feb 9, 2019 at 21:01
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    @Alaskaman, it will break for sure. I would give it 3 months at most. The OSB flexing will destroy the tiles
    – Quoc Vu
    Feb 11, 2019 at 19:49

I JUST did this in a laundry room.

  • Cement board is a must.
    • Don't skimp on thinset or screws.
  • That small of area will not require a leveling system; you can manage with a rubber mallet.
  • Use a toothbrush to clean the grout lines while laying the tile to avoid cleaning up after it hardens.
    • Always have two buckets of water, rotating for cleanliness.
  • The Schulter profiles are amazing.
  • I used MAPEI Flexcolor CQ for grout; one of best DIY products ever.
    • Water cleanup, but won't stain.
    • Forget the sponge; use a microfiber cloth folder over. It is unreal how much those things pick up. I cleaned with vinegar and water after curing, but I am not sure that I even had to because it picks so much grout up off the tiles.

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