# Tiles coming loose over Ditra.



## NCFHOME (Dec 7, 2014)

I am no tile pro by any means but occasionally I do small tile projects. Over the past few years I started to use the Schluter ditra underlayment. However the past three jobs I have done I have had tiles come loose. Each time it has happened I would think my mixture is too dry or my trowel size was wrong. I would re read the schluter installation hand book and the thinset instructions and it seems as though I did everything right. All of a sudden it dawn on me that I am use Non-modified thinset as the ditra says is proper. I few years ago I was using just regular TEC brand thinset from lowes and never had a problem ever. But I started to use the non modified TEC brand mortar that says on the bag" specially formulated for uncoupling membrane"

I pulled a tiles up today and it was like the mortar didn't stick to the back of the tiles. I had plenty of thickness with good notch squish. It simply didn't stick to the tile.

Am I not mixing the non-modified correctly? Is the non-modified no good for setting tile?

I have used several different brands of non-modified and its happened to them all.

Any advice is greatly appreciated.


----------



## kevjob (Aug 14, 2006)

Did you burn the backs of the tiles with mortar using flat side of trowel assuming the tiles were porcelain? Same on floor before troweling with the teeth?

Wipe any dust off tiles or drying cuts before setting? 

Vacuum ditra before setting?

Porcelain tiles like modified, Schluter wants un mod over it. I use modified all the time and never have any issues but I won't get any warranty support.


----------



## MIKE ANTONETTI (Jul 17, 2012)

The word "stick" people assume thinset is a glue. It has to be worked into the tile, to mechanically lock into. You should work the tile into the thinset, with a slight rocking back and forth while pressing down. Then pull it up to visibly see the bond. 

There are many reasons why a tile is not "bonded to thinset, Ditra actually reduces the number of causes by not robbing the moisture out of thinset.


----------



## Golden view (Feb 16, 2012)

back butter back butter.


----------



## tjbnwi (Feb 24, 2009)

Schluter instructions now include the back butter recommendation. Makes a very big difference.

Tom


----------



## CO762 (Feb 22, 2010)

I hope you're doing this tilework in your home and not on anyone elses.


----------



## Eaglei (Aug 1, 2012)

Very simple test , after you set the tile try pulling it off the wall or floor . 
If you have trouble pulling it off right after you set it that's a good bond .
If it comes off easily then your not doing something right . Probably your mix wasn't hydrated properly . You would've saved yourself a lot problems by doing this . As others mentioned burning the backs of the tiles with thinset makes the bond extremely strong but you still have to have the thinset mixed properly .


----------



## charimon (Nov 24, 2008)

switch to Ardex A5 if you want to use a modified mortar with Ditra and retain a manufacturer warranty. Ardex will back it.
http://www.ardexamericas.com/en-us/Products/tilestone/Pages/X5.aspx


----------



## CO762 (Feb 22, 2010)

Eaglei said:


> Very simple test , after you set the tile try pulling it off the wall or floor .
> If you have trouble pulling it off right after you set it that's a good bond.


I think that test is in all 856 different how to books on tile.


----------



## AGullion (Apr 19, 2015)

In my opinion it's suction . what I look for is coverage


----------

