I’m doing my first solo tile job, and I’m ready to grout the floor, but I’m not sure what sort of prep I should do near the edge of the bathtub.

Obviously, it should be caulk when I’m finished, not grout at the transition— but should I caulk first then grout? Pack something in the grout line, grout, then caulk? And if I go that route, what should I use to pack in the gap? Or is there some other technique that I haven’t considered?

Also, I don’t know if it’s significant, but I suspect I left way too wide of a margin when cutting the tiles (Almost a 1/2”),/9 if that might affect the answer, please let me know. I might go back and put down some quarter round if it’s really bad, but for now I’m just going to caulk it.

The closest question that I could find on here was about someone relaxing the caulk, not a new tiling job: Correct order of operations for caulking + sealing bathroom tile?

2 Answers 2


Since you haven't grouted yet, use epoxy grout. It is waterproof and doesn't need to be sealed due to it being non porous. You should grout right up to the tub since the epoxy grout won't crack like regular grout will. Then put a small bead of caulk between the grout and tub since the epoxy grout might nor totally adhere to the smooth surface of the tub.

Read all the instructions for epoxy grout. It's more difficult than using regular grout but it's so much better.

  • I agree and started using epoxy grout a while back it prevents cracking in corners and at the floor tub and wall tub interface where I still use a quality silicone seal as that is where the most movement is.
    – Ed Beal
    Apr 9, 2022 at 19:08
  • Hmm. This might be a problem as my grout lines are pretty tight everywhere else (1/8th or 1/16th inch…. I was using two different sized tiles as it was from a salvage place). Or does epoxy grout not have the sanded vs unsanded issues?
    – Joe
    Apr 9, 2022 at 20:10
  • 1
    @Joe This won't be a problem because the epoxy resin bonds with the sand and can be used in your 1/16th grout lines whereas regular sanded grout would not.
    – JACK
    Apr 9, 2022 at 20:34

Yes, 1/2" is a rather large gap to fill- typically against a tub the tile should be tighter. Then that joint can be just caulked.

Replacing those tiles against the tub would be the first option.

If that is not something you want to do then I would first use grout to fill the large void. Then apply caulking over that and possibly still a trim of some sort to cover the large line there.

The caulk is an important step to dissuade water from getting down under the tile. And this joint against a tub is where it is quite possible that water will be splashed and potentially go unnoticed. Most grout manufacturers provide a caulk which matches the grout color- sanded if you are using sanded grout or smooth if you are using a non-sanded grout.

  • I can’t replace the tiles. They came from an architectural salvage place, so I don’t have enough to replace them. My only option would be to cover the gap afterwards if it comes out really bad.
    – Joe
    Apr 9, 2022 at 20:07
  • "Next time" - with any tile project, but particularly salvage tile, get some extra and save it. Preferably labeled for where it belongs if not blatantly obvious.
    – Ecnerwal
    Apr 9, 2022 at 23:22

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