# Tiling the Bath - process/material improvements



## artinall (Aug 14, 2007)

Whenever I tile, I've always stuck with thinset. Not easy to mix but that grip never seems to release.

Now on a bath - I'm faced with tiling right across the surface of a slab control joint. Isn't there a membrane or matt that can be applied atop the concrete that will greatly eliminate the possibility of cracking (ceramic or porcelain) ?

What might be an improved method over the thinset? High moisture propects... Have never applied a premix directly -- only done corrective work following failure! I know the mixes are easier to work (besides the mixing, they are lighter to lug around - no minor thing as the years press on!)


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## Frank Castle (Dec 27, 2011)

Ditra to isolate. Thinset on both sides of Ditra.


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## artinall (Aug 14, 2007)

Frank Castle said:


> Ditra to isolate. Thinset on both sides of Ditra.


 Over the complete area or only around the joint?


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## overanalyze (Dec 28, 2010)

I have had similar thoughts/concerns. The last slab tile job, I had a few control joints as well as 1 crack in the slab. The slab was several years old and all cracks/joints were in plane. I filled with Planipatch first. Then I put a heavy coat of crack isolation membrane coating across the joints. Then I tiled as normal. I anxiously await being scolded and corrected by fellow tile guys here...


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## Tom M (Jan 3, 2007)

I think you bridge the crack with the membrane but use soft joints on each side of the tile. I would have to look it up but I think thats the deal. Ditra also provides very good details on all kinds of scenarios


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## TaylorMadeAB (Nov 11, 2014)

Ditra across the whole field is about the best you can do in that situation IMO 


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## TNTRenovate (Aug 19, 2010)

Rule: All control joints must be honored.

That means that you can't just tile over them with anything and think you are done. The control joint is there for a reason. If you don't honor it with your finish, you are asking for trouble.

Adhere to EJ171 and the TCNA recommended installation guidelines for tile over concrete. They have tested this more than any of us combined, so there is no reason to try things that someone on the internet said might work.

You can also contact Schluter and get their tech dept to give you recommendations on what products to use. Schluter has some fantastic control/expansion joint profiles.

The 2016 TCNA handbook is a must. Your application starts on page 62.


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## TaylorMadeAB (Nov 11, 2014)

TNTSERVICES said:


> Rule: All control joints must be honored.
> 
> That means that you can't just tile over them with anything and think you are done. The control joint is there for a reason. If you don't honor it with your finish, you are asking for trouble.
> 
> ...




Are we talking control joints or isolation joints? No question that iso-joints need to be continued throughout the floor. I hadn't really considered control joints to be more than a way of choosing where a crack occurs in a slab, if it in fact does crack. I was under the impression that Ditra would allow the slab to shift if needed, but keep that shift isolated underneath. 


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## TNTRenovate (Aug 19, 2010)

TaylorMadeAB said:


> Are we talking control joints or isolation joints? No question that iso-joints need to be continued throughout the floor. I hadn't really considered control joints to be more than a way of choosing where a crack occurs in a slab, if it in fact does crack. I was under the impression that Ditra would allow the slab to shift if needed, but keep that shift isolated underneath.
> 
> 
> Sent from my iPhone using Tapatalk


Ditra will only allow so much "shifting" I believe it's 1/8". Any more than that and you create a failure.

But as far as I was taught and know, you respect a control joint, iso-joint, expansion joint...you respect the joint. I would most likely install Ditra on top, but would also install a soft joint.


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## Frank Castle (Dec 27, 2011)

TNTSERVICES said:


> ...you respect the joint....


And don't Bogart it!:laughing:


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## Willing2win (Mar 6, 2017)

I'm with them... Ditra is a great product, a little pricey for some jobs but with the money if you warranty your work and factor it into your bid.

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## artinall (Aug 14, 2007)

If I soft joint it, I believe that it will show against the rest of the grout lines. This is a control joint very prominent across the floor, right after you walk in.

If I understand it correctly, the tile council recommends tile spacing on either side with a wide grout joint. That would be one wide joint.


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## TNTRenovate (Aug 19, 2010)

artinall said:


> If I soft joint it, I believe that it will show against the rest of the grout lines. This is a control joint very prominent across the floor, right after you walk in.
> 
> If I understand it correctly, the tile council recommends tile spacing on either side with a wide grout joint. That would be one wide joint.


A soft joint is for finished floor material expansion. An expansion joint is for slab foundation movement management.


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## Itsthetajmahal (Jul 24, 2017)

Yes if the concrete joint is square with the room that would probably be your best bet to split a fat joint on it if it looks that threatening. I'd go with the detra though


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## artinall (Aug 14, 2007)

Going with the ditra - I'm figuring 3/4 total floor height after tile.

The bordering room has carpet. 

So I'm looking at finding the best transition to make up the difference in floor heights.

Either a carpet ramp up to it...or something like Schulter Reno? But I really don't know for a carpet layers standpoint how tough it might be to tuck that carpet beneath the metal fold.


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## tjbnwi (Feb 24, 2009)

Ditra XL will get you to 3/4". If you use XL you need to use a 1/4" notch trowel to set the the XL not the Ditra trowel.

Try to leave the carpet long, roll and staple the edge, set will 2x and rubber mallet. 

Tom


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