Shower Tile?

Richard S
by Richard S
I have installed backer board to all walls and am ready to start tiling them. Want to tile over the floor tiles, but the posts seem to discourage this. Seems like a real project to remove the tiles from the concrete shower floor. Then left with problem of smoothing it to accept the new tiles. Is tiling over the existing floor tiles really looking for future problems? If not, do I need to rough up the floor tiles before I put down the new on top of them?
  14 answers
  • S and W Kitchens, Inc. S and W Kitchens, Inc. on Oct 17, 2011
    Please install the floor first...not the wall tile. You answered your own Question about future problems. Take up the old floor before you put down the new one....be sure the new floor is properly sloped towards the drain...If you have an average sized shower, should be around 20 square feet max. Be well worth the effort to do it the best way.
  • Yes, flooring 101, never tile over existing floor, your are looking for trouble. Always start fresh, it;s more work but you will never regret it.
  • 2ms2 2ms2 on Oct 17, 2011
    Do. Not. Do. It. :)
  • Tile on top of other flooring has been done in a pinch - like over vinyl flooring in kitchens or foyers, etc. (not something we have personally done, though) However tile over tile is really looking for trouble due to the porous nature of grout. Then, adding water to the mix by putting it in the shower is just bad news. I know you were hoping for an easier answer, but unfortunately the only way to really do this project well is to remove the floor tiles and lay the new ones before the wall tiles.
  • KMS Woodworks KMS Woodworks on Oct 17, 2011
    Richard one tool I have found to be indispensable for tile demo is an air chisel...I have used it on dozens of projects. It take 95% of the work out of tile demo...especially tile demo on concrete slabs. The chisel itself is pretty inexpensive ( about 40 to 50 bucks) you will need an air compressor to use it. I use a basic 4 gallon twin stack...and need to wait a bit as this chisel has a high demand...a larger compressor would be much more effective. In some cases I have hooked both of my compressors in parallel to supplement the supply. Renting a larger unit is also another option. With the chisel you could demo the tile in no time....rough thinset residues can also be chiseled away or ground down with a cup stone on a right angle grinder...very small debris can be covered with "level mix" or a thicker bed of new thinset for the new tile. Tiling over old tile is something you NEVER want to do. As a Safety Note you will want some safety glasses and or goggles and some heavy leather gloves and a dust mask...the chisel will kick up sharp bits of tile and make a bit of dust. look at this project.... http://www.hometalk.com/Kevin/project/2181 in Photo 10 you can see my chisel in use.
  • Joe Washington Joe Washington on Nov 03, 2011
    I'll add to the chorous of those saying "don't do it". Do the real work up front. If you're just talking about removing tiles from the floor of the shower it shouldn't be a big job. There's no substitute for doing it right the first time.
  • The drainage system is also connected below the tile floor area. Shower drains have an above the surface drain connection and a below the floor connection to catch and drain water that the drain pan under the tile collects when grout fails etc. By putting tile over the existing tile on the floor. You risk perhaps messing up this system causing early floor failure. As it is now water that gets under the existing tile is allowed to drain down towards the pan in which it collects and finds the drain because of the slope built in. If you place the tile over tile, water that will seep under the new tile will become trapped by the old and in effect you will create a layer of water that cannot go anywhere. The end result will be a loss of binding between the old and the new over time, resulting in tile adhesion failure. Removal is not as hard as you would think. Using a mini jack hammer with a flat blade it should take no time to remove the tiles by scraping them off the old base. http://www.hometalk.com/feeds/my-network#
  • Richard S Richard S on Nov 03, 2011
    I took all of your advice and borrowed an air hammer. Took 5 minutes to remove the tile and turned out a bunch of it was already loose. Thanks for convincing me. Now I am confused about the seams between the backer-boards and corners. Mfg says to use thinset mortar mix with tape, but boxstores direct me to products that seem to be for another use. Is the thinset mortar mix the same as the thinset glue for setting the tile? If not, where do I get the right product for the job?
  • I would simply use this product to seal the floor and the walls. You use unmodified thin set mortar to install it and then a few hours later use the same material to place your tiles. http://www.schluter.com/8_1_kerdi.aspx Be sure to check out the entire site. They have some very useful information about doing showers.
  • KMS Woodworks KMS Woodworks on Nov 04, 2011
    I've used the regular fiberglass mesh tape that is routinely used in drywall applications...that and regular thin set. Keep in mind that each "layer" of the building process adds its own resistance to moisture. 1. the backer 2. sealing the joints with thinset 3. the tile 4. the grout 5. the grout sealer
  • Richard S Richard S on Feb 06, 2012
    Thanks everybody. I took your advice and removed the existing shower floor tile. Amazing how many loose tiles there were. Job now done and looks great.
  • KMS Woodworks KMS Woodworks on Feb 06, 2012
    done right the first time...congrats
  • And now you know with comfort that your leak will not be an issue.
  • S and W Kitchens, Inc. S and W Kitchens, Inc. on Feb 07, 2012
    Excellent to hear...love to see pix if you ahve them.