The contractor's intent was to leave a gap at the bottom of this tile job, to allow drainage, and as an alternative to a caulk job requiring periodic maintenance:

No caulk gap at bottom of tile shower

However it did not work, the gap is too small. A bead of water forms (via surface tension) and sticks there long enough it's still wet by the next shower.

The tile is talavera style, unglazed at the edges and relatively porous. The lip on the shower pan goes up about 15mm. The present gap is about 3-5mm. There's hardy board behind the tile.

I'm thinking a larger vertical gap would have worked. If you were going for a no-caulk tile in a case like this, how high would you have set the first course?

  • 2
    I would definitely not cut it larger at this point. You might get it higher than the lip on the shower pan. You could leave it as it is and see if weekly spraying or wiping with chlorine bleach (or commercial equivalent) would prevent mold formation, but since the tile is porous you should probably caulk it to prevent water from getting in. Black silicone might give a nifty appearance. Commented Dec 20, 2018 at 0:17
  • The lip on the shower pan goes up about 15mm. The present gap is about 3-5mm.
    – Bryce
    Commented Dec 20, 2018 at 2:08
  • Silicone caulk for shower and tub? what gap is appropriate at the bottom of tile? - it's whatever you choose to fill it with, that it says on the bag of grout or tube of caulk, what its minimum required thickness is. But that's not what I would use as a criteria for choosing a material. Too small, w/e: grout it IMO. That just means it might crack someday. Should there be a weep gap? no.
    – Mazura
    Commented Feb 2, 2019 at 17:41

2 Answers 2

  1. Fire your contractor. The tiles aren't set square, the grout lines look HUGE, and the grout is discolored.

  2. Caulk the entire perimeter. You might allow a 1 inch horizontal gap on each side for a weep hole as suggested by @freshop.

  • The talavera style tiles are deliberately "handmade", somewhat lumpy and uneven. The grout color is due to years of use. The tile job is professional, the bottom spacing was a contractor mistake.
    – Bryce
    Commented Dec 21, 2018 at 17:49
  • 1
    Perhaps it's just the point of view of that shot, but the tile on the left wall in the corner doesn't look square. The grout lines are so much wider than I would like (though that's probably a matter of personal taste), and they look uneven (e.g., the width of the grout line changes under the feature tile on the right).
    – Paul Price
    Commented Dec 22, 2018 at 18:28
  • 1
    Note that's an inside corner tile: those were custom made for this project and came out kinda uneven. Still the question on the table is: what gap is appropriate at the bottom of tile?
    – Bryce
    Commented Dec 23, 2018 at 6:17
  • 1
    The current gap between the tile and the tub of 3-5 mm is fine. Just caulk it.
    – Paul Price
    Commented Dec 24, 2018 at 2:49

1 inch. So caulk it but leave a 1 inch section uncaulked as a weep hole. Just leaving that inch (per side) uncaulked will be enough to relieve hydrostatic pressure of any water that gets behind the tile. That water wants to go down because of gravity, but if you completely caulk around the gap it won't be able to escape easily and would leave moisture behind your caulking and eventually stains will come through.

  • What's the minimum? The shower pan lip is only 3/4".
    – Bryce
    Commented Dec 20, 2018 at 2:09
  • 3
    The 1 inch suggested here is an horizontal gap. @Bryce is asking about a vertical gap.
    – Paul Price
    Commented Dec 20, 2018 at 2:56
  • @PaulPrice correct. I'm considering grinding out a larger vertical gap. That or caulk and leave a small horizontal gap (which will have the same vertical gap problem).
    – Bryce
    Commented Dec 21, 2018 at 17:50

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