Bathroom Floor Tile—Installation

—from an e-mail I once sent in November 2012...

Please read these instructions all the way through several times, just as if you were making a recipe so that you understand the outcome. If you blindly go step-by-step, you'll find you obeyed a step without understanding and that this screwed up a later step because you failed to coordinate the implications of both in the final result.

Much of this is useful in totally fanciful tiling situations like a custom soaking tub my daughter put in her massage business.


  1. Purchase tile, backerboard, floor screws, adhesive, spacers, grout and sealer.
  3. Assemble tools: toothed trowel, tape measure, chalk line, grout float, rubber mallet, level and ceramic tile saw. Also other incidental tools like screwdrivers, putty knives, utility knives, water basins, etc. Consumables: cloths and big sponges.

Room layout

  1. You want tiles to look nice going in, so probably assume a full tile smack in the center of the doorway upon entering the room.
  3. However, choosing to begin layout there must not also result in awkward, ugly or inadequate tile elsewhere, particularly in visible places. For bathrooms, this is rarely too much of a problem.
  5. Lay a few tiles including spacers out from the first one to see if your layout will be agreeable. Adjust for any awkwardness.
  7. Once you've reached the tub (assuming that's the deepest part of the room, measure for the first course of tile and note. This means that the course will likely consist of tiles that are cut up against the tub.

Install backerboard

  1. This step overlaps the layout somewhat: Install the backerboard with your knowledge of where the tiles will sit. The point is not to have too much going on where edges of tiles will sit directly above backerboard edges as this will likely result in a crack. A little of this may be unavoidable, but don't let it happen much. Don't create "four corner" areas with the backboard, but stagger them like bricks in a wall.
  3. Install backerboard using screws and, depending on type of board, tape and joint compound (not drywall stuff, mind you: this is real masonery here).

Install tile

  1. Remeasure and mark backerboard for first course of tile and also snap a line down the center of the room to the doorway to help you stay on an even course. You do not need to register every tile, but you do need enough registration to keep your work accurate and on course.
  3. Mix up the adhesive. For a floor, this is a masonry product more or less like brick mortar. It should be like brown sugar with lots of butter in it. When you draw a toothed trowel through it, the trowel should move easily, but the adhesive should not slump down, but leave distinct tool markings.
  5. Beginning near the tub, spread adhesive out using the trowel over an area not so large that you can't reach the tub and/or wall in order to have complete control over placement of the tile. Be careful that, despite the adhesive, you aren't disoriented because the registration marks you made are all covered up and you lose track of where your tiles go.
  7. Carefully place tiles where they go using spacers to keep them even. Once you're away from the tile and there is no risk it will be disturbed, you can remove the spacers.
  9. Do NOT press down carelessly on the tile. The reason for the tool markings is so the tile will sit up with room for the adhesive to compress down just a little and allow you to level the tiles to each other. Level the tiles by site, tapping very carefully as you go to seat them. Once you're through with a large area (that you can still mostly reach), use a piece of backerboard or other rigid sheet stock to level all the tiles together.
  11. If in leveling either when tapping initially or using rigid stock later you squish adhesive up between the tiles, you're in (some) trouble. This is undesirable. You can us a flat-blade screwdriver to clean up the leaked adhesive here and there, but you don't want to make this the rule. What's happening? Bad: you're seating the tiles with too much pressure. Really bad: your adhesive has too much water in it. This instruction, in particular, is one you need to grok in terms of how to perform earlier ones. (I warned you about this.)
  13. Continue installing adhesive and tile, plus leveling the tile until you're out the door.
  15. Let everything sit undisturbed for at least 48 hours (or what is marked on the adhesive bag).


  1. Clean up the newly tiled floor now that you can walk on it. Get rid of any little bougers of adhesive that might shred the grout float as you pass over them. Chisel out any lines between tiles that are filled with adhesive that will keep you from putting grout into them. (Knowing you'll have to do this--and it's a super pain to have to--while you are installing the tiles in the first place is yet another reason to have read and re-read these instructions before getting started.)
  3. Mix the grout according to instructions. I must be thin enough to spread, but not so thin that it cannot be "worked" nicely between tiles using the float.
  5. Begin where you began tiling two days before. Spread the grout over the tile seams using the float. Don't put any more grout on tiles than just occurs naturally as you work the seams and clean the tile surfaces using the grout float as you work to minimize the build up.

    Note that you can use grout between tile and wall, but you cannot use grout as a construction component between tile and nothing (that is, between tile and air, carpet, carpet strips, etc.). However, if you're going to caulk between tile and wall, or tile and tub, or tile and tile, don't grout there. (A little grout in the transition isn't a show-stopper, just avoid getting a lot in there.)

  6. Tool the grout as you go by swiping obliquely across the seams with the float. Pay attention that your tooling doesn't pull grout from the seams. The finished grout should sit slightly lower than the surface of the tile. Do not succumb to the temptation to use a corner of the grout float to finish a seam: this isn't brick and mortar.
  8. If you need to return to old areas, use stiff sheet stock such as clean backerboard to protect ares you've already grouted but need to step on.


  1. While the grout is still not dry, using a very big sponge that you keep very clean, start again over the grouted areas and wash the tile surfaces without dripping water into the grout lines. Pass over the grout lines taking care not to undo the tooling you've done; don't pull any grout out of the seams. There will be some cloudiness left on the tile, but remember that the more grout left over on the time, the hard final clean-up will be.

Final clean-up

  1. Once the grout is pretty dry, maybe half a day after grouting, go back again and clean the tiles with sponge and water. This time, clean them very well. Take care not to disturb the tooling of any grout that's still not resistant to the sponge.


  1. 48 hours later, or whatever the grout package says, come back and re-clean the tiles if necessary. Seal the grout using lemon oil or a special grout sealer purchased for this purpose.

Restoring the room

  1. Replace the baseboard, directly on the new tile.
  3. Reinstall the toilet using new wax ring, or even two wax rings including one of them with a black plastic collar, to ensure no leaks.
  5. Step back and appreciate the beauty.

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