Grout - How thick is too thick, and how to build up a low area?

imautoparts · 12-15-2012, 03:40 PM

Hi all. I took some advice from here and am redoing the lower portion of my 1968 shower as I had greenboard backing and it started to deteriorate. I was told to use cement board per modern practices vs replacing/repairing the greenboard so that is what I did.

I have one section where the studs aren't quite squared up properly. I'm not willing to completely open the walls to reset the studs, but after I mounted the cement board I can see that I'll have to build up or fill along that section to keep the tiles even with the rest of them. At the spot that is the most indented I'll need to about double the thickness of the mounting grout to achieve a good fit. The area in question is in a lower corner - by shimming etc I only have a small area that will require extra fill.

How thick can I grout? Is there a particular type of grout that is recommended when you have to put it on extra thick? How do you trowel the grooves into grout when it is thicker than the cutouts on your tool? Any other information or suggestions?

Thanks - sorry for being such a noob

**oh'mike** · 12-15-2012, 04:34 PM

You are using the wrong words,I think---Grout is the stuff that fills the gaps between the tiles after they are set ---

Tiles are stuck to the wall with THINSET---( A powdered cement material)

You are doing a repair and some place is lower than the existing tile?

If that is the case---mix a small batch of thinset----skim coat the wall in the shallow place and wait for that to set up----then trowel the thinset on and set the tiles---

Using wet thinset to fill a void and set the tile at the same time seldom works well--the mud sags and pushes the tile out of place---

imautoparts · 12-15-2012, 05:07 PM

So you must use two products? I guess I've been lucky - I've got a big tub of something that I've been using for minor patch jobs for years. It's called "Tile Perfect" pre-mixed ceramic tile adhesive and grout (no sealer needed). That is exactly what is written on the tub.

What would you consider to be the best quality thinset to use? I want this repair to be stable for years.

**oh'mike** · 12-15-2012, 05:12 PM

You want powdered modified thinset---I prefer white for walls but grey works welll--then you want a powdered grout---

What you have is an organic adhesive----water based glue---not good in a wet area, as it will soften up when it's exposed to moisture----

rodneydnelson · 12-15-2012, 05:25 PM

I had the same issue with a wall this week. I built out the low area in the wall with thin-set mortar and let it cure over night before tiling the next day. I use Ultraflex II, a polymer modified Mortar by Mapei.

imautoparts · 12-16-2012, 04:50 PM

I'm going to use the suggested brand of thinset, but since as an old automotive guy I'm just not comfortable with so much "free floating" filler, I've acquired some of this stuff:

I'm going to cut it into strips sized to fit the problem area, and then apply a coat of thinset, then a fiberglass strip, then more thinset to build to the correct depth. That's gonna be the toughest part - determining how thick is thick enough without going too far.

I'm goint to try to err to the side of "less is better" and then make it up with the actual adhesive layer to the tiles.

Plenty of time to dry before applying the tile layer of course. Does this make sense?