[Kspann]

Hello All. I was tasked with replacing a cracked tile and some grout that was crumbling. Never done tile floor before but I have repaired a tile in a shower wall and have done several backsplashes with no issues.

So I use the oscillating tool with attachment to remove the grout and there was no issues with that. I also remove the cracked tile but I find that I am able to see really far down... maybe 1/2 to 3/4 an inch. I clear it out and there is a rather large crevice that needs to be filled.

In the garage, I find spare tile that the previous owner had ... and lucky me, a partial bag of TEC Power grout that was used. So I cut the tile to shape, and mix the grout to what looked correct to me. Laid the tile with thinset... filling that whole and paused for 24 hours. Then I applied the grout. I waited the incubation time between each step and it looked great.

Next day, wife took a shower and the grout came right out. I showered after her and noticed it. I also noticed a white milkyness coming from the freshly laid single tile. After investigation, I touched the tile and it sank and oozed the thinset. So I think something went wrong.

Looking for some advice here on how to fix this. I thought Power Grout was supposed to be super awesome stuff. Maybe it expired?? How should I fill that cavity for the tile?

Thanks in advance.

 

[chandler48]

What happened after the last picture?? How long has it set up?

 

[Kspann]

What happened after the last picture?? How long has it set up?

26 hours later, the new grout washed out. Well around 75% of it. The tile pushed down into the thinset after that wash. It has been 36 hours since the shower that washed out the grout.

 

[chandler48]

If you used pre mixed thinset, that is a problem. It does not cure well. Face it, it has been sitting in that container for ages and hasn't cured. You should be using powdered modified thinset, mixed to a good consistency. I agree that your grout may have "expired" and for the cost of a new bag, I wouldn't have put it on my floor, knowing it was old stock.

 

[udraft]

Yes, fresh thinset, fresh grout (just read it expires after 1 year??). Let it set up for say 30 hours. Possible the drain is not solid, moving up and down, could cause issue.

 

[chandler48]

That looks to be a Schluter system, so hopefully it isn't punctured anywhere.

 

[Dave Sal]

Personally, I would recommend applying a grout sealer once it's fully dry. This will prevent water from penetrating the grout.


https://dupontstonetech.com/collect...e/products/stonetech®-heavy-duty-grout-sealer

 

[jeffnc]

Grout sealers and "fresh" thinset have nothing to do with it. (You should never seal grout for the purposes of waterproofing - you seal grout to avoid it getting dirty and for easier cleaning. Showers must be waterproofed in other ways.)


I agree with Chandler that this is probably a Schluter system. That "gap" you see is part of the way the pan dips down toward the drain and is not a problem - just fill it in with thinset.

The most likely explanation is what Chandler also said - it's a premixed thinset. Don't ever use a premixed thinset in a shower application. Buy the powder that you mix yourself. Unfortunately you'll have to buy more than you need for such a small job.

 

[jeffnc]

You should be using powdered modified thinset

Unmodified in this case, actually.