Tile on existing concrete shower floor
This is a bit of a variation on questions I’ve seen posted. I’ve got an old basement shower with a concrete floor. The concrete comes up about 4 inches (including a curb at the opening) and above that there’s a fiberglass liner for the stall. The concrete floor is almost flat (not sloped to the drain), and though it’s decades old, there are no cracks or leaks.
I want to tile with 2×2 mosaic tile, and create a proper slope toward the center drain. I’d appreciate any advice about approach in this situation. Just build the slope with the thinset and lay the tile? Or do I need to get involved with layers and membranes?
A second question is assuming I also tile the short vertical concrete sides of the pan, managing the line where the concrete meets the fiberglass liner.
Thanks!
Replies
Thinset is an adhesive and is not made to be used as concrete. Tear the whole thing out and start over with a dry mud pre-slope, vinyl pan liner, and final slope. Lay your tile and that and all will be well.
First, you need to determine the height of the shower drain. Keep in mind that the tiles should be laid level or 1 mm higher than the top edge of the shower drain, to ensure optimal water drainage. When calculating the total depth, please take into consideration: tile thickness, tile adhesive layer and levelling layer.
Thanks!!
Does it drain now?
So glad I found this community!
@Mike_Mahan, depends what you mean. The floor is too level so the water does not run to the drain well, but the drain itself works fine.
I got this advice yesterday from a contractor friend:
1. Since there are no leaks, no cracks, no issues with the drain, use just a layer of Flexbond to both build the slope and lay the tile (then grout of course)
2. Leave the existing drain alone so as not to risk creating a whole new set of problems, cut the tile to shape around it, seal around the resulting circle with silicone
This is all obviously a more simple approach. Sound like a big mistake?
Thanks again!
I’m no tile guy but I have seen my fair share this is a list of issues I have observed over the years with using mosaic tiles some are obvious . as for your pan I think it needs a water proof menbrane or system . But it its been working all these years redlock it an cross your fingers. Thats a tough call if it was a clients home I would definitely put a new system in Hope the notes below help
You cant cheat a 1/16 on mosaic like you can with solid tile. The grout lines
on the mosaic shift . The section may maintain square on one side not on the other .
The way you dry fit dictates how you lay it . The mesh on the back has overlays that create an interlock . You can cut them if you need to do a drop in don’t try to tuck under wet tile .
Does grout hide the shift in grout lines on mosaic ?? Sometimes
Seal marble before grouting
Does floating work with mosaic?? Not easily, when you use a large notch or set the tile high it is much easier to push the mosaic down too far causing the grout lines to fill from the bottom
When setting mosaic look in the grout lines for a small amount of thin-set to push through the mesh .
When fixing one small tile ,gorilla glue / construction adhesive works well make sure it bulges out( at the floor not the top ) just enough to create a bed for each tile .
To cut small tiles,cut on foam or slivered foam to create shock absorber. Hold tile firmly on both sides
Create jigs to hold small tiles flat on saw
Raw marble stains easy
Don’t be afraid to stop just one more row could kill you.
Good Luck
Mikesa7, what a great set of notes and tips! Many thanks!