Which tile adhesive to use with Schluter Ditra - Tile Advice

[Franer]

Hi guys, I'm a homeowner and a DIY enthusiast. I have two small areas to tile. A front hall and a pantry area. Ceramic tiles (small) and using Ditra matt. Both areas are over concrete. From my research online they say it is important to use unmodified mortar. I live in Dublin Ireland. Any advice on which type and brand of adhesive I should use. I know unmodified is an American term and part of the problem was that my info was coming from US sources. Thanks in advance for any help offered.

 

[Dave]

Hi , what reason are you using Ditra for firstly and as for adhesive, yes your info is American based , schluter uk say modified adhesive is fine.

 

[Franer]

Hi , what reason are you using Ditra for firstly and as for adhesive, yes your info is American based , schluter uk say modified adhesive is fine.

Hi and thanks for the reply. I'm using Ditra because there are a few small cracks in the concrete and I'm hoping the de-coupling matt will prevent and movement in my tile down the line. I am also trying to build up to the height of a laminate floor so the few millimetres I'll gain in height will be useful. So any flexible polymer enhanced adhesive will do? On Shluters website they do mention that it may have drying problems. They recommend modified when laying Ditra onto a wood substrate but when laying the Ditra on concrete they say to use an unmodified and for laying the tile onto the Ditra they also say use unmodified. Thanks again for the reply I appreciate your advise enormously.

 

[MitchellGloverLondon]

Use a 3/4mm notched trowel, mix a good quality rapid runny, make sure to rub it in, and make sure you prime if substrate requires.

 

[Franer]

Use a 3/4mm notched trowel, mix a good quality rapid runny, make sure to rub it in, and make sure you prime if substrate requires.

Hi and thanks for the reply. I'm aware of how to install the Ditra and what trowel to use, what I am unsure of is which tile adhesive to use. Have you used flexible adhesive or polymer modified to install tiles on top of Ditra? As the previous posts explain Shluter don't recommend using a modified mortar. Thanks again for your input.

 

[Dave]

Hi and thanks for the reply. I'm using Ditra because there are a few small cracks in the concrete and I'm hoping the de-coupling matt will prevent and movement in my tile down the line. I am also trying to build up to the height of a laminate floor so the few millimetres I'll gain in height will be useful. So any flexible polymer enhanced adhesive will do? On Shluters website they do mention that it may have drying problems. They recommend modified when laying Ditra onto a wood substrate but when laying the Ditra on concrete they say to use an unmodified and for laying the tile onto the Ditra they also say use unmodified. Thanks again for the reply I appreciate your advise enormously.

Go to schluter uk not .com.

 

[Franer]

Go to schluter uk not .com.

Hi again, I copied this from Shluter UK - "Immediately after the Schlüter®-DITRA 25 matting is installed, the tiles can be set using the thin-bed method and using a bonding tile adhesive that matches the requirements of the covering."
So they are saying it doesn't matter but the US Shluter site has a whole article about modified/unmodified, I find that odd in that they are talking about the same product. Have you used modified mortar on Ditra without any problems in the past? Thanks again for your help

 

[MitchellGloverLondon]

Hi and thanks for the reply. I'm aware of how to install the Ditra and what trowel to use, what I am unsure of is which tile adhesive to use. Have you used flexible adhesive or polymer modified to install tiles on top of Ditra? As the previous posts explain Shluter don't recommend using a modified mortar. Thanks again for your input.

Flexible adhesive, Ardex x7r should be fine.

 

[Lou]

@Schlüter-Systems Ltd can you help out?

 

[Old Mod]

You’ll find that most installers in the uk will use the same adhesive under as well as over Ditra25
An S1 adhesive will work perfectly ok,
an S2 however, will not.
And yes, there differences between Europe and the U.S.A. when it comes to methods of installation etc.
Then, they have a Ditra25 cement based adhesive available to them, we don’t.
And yet it’s a European product.
So If you follow the guidelines laid down by
Schluter.co.uk you will be covered,
but not by Schluter.com.
You can also ring Schluter Uk direct and talk to their tech line.

And just as a footnote, if memory serves, in the USA although they use the term
‘unmodified thin-set’ the adhesive still works with porcelain, and by that definition, it must be slightly modified, or it wouldn’t work.
I believe their ‘modified thinset’ is more akin to our S2, and then that statement is correct, it should not be used with Ditra25.

If anyone wishes to correct me, please do.
I’d be as interested as the OP.

 

[Franer]

So should be ok with this? S1

 

[LM]

So should be ok with this? S1 View attachment 110989

If you can buy Evo Stik locally go for their standard set OPF which is now an S1 also.
A rapid set adhesive will make your task much harder as it’ll put you under pressure with the adhesive setting to quickly.
Be sure to back butter the tiles with the flat side of the trowel.

 

[Dave]

Hi again, I copied this from Shluter UK - "Immediately after the Schlüter®-DITRA 25 matting is installed, the tiles can be set using the thin-bed method and using a bonding tile adhesive that matches the requirements of the covering."
So they are saying it doesn't matter but the US Shluter site has a whole article about modified/unmodified, I find that odd in that they are talking about the same product. Have you used modified mortar on Ditra without any problems in the past? Thanks again for your help

Yes i have today. Lol.
We’ve had thus conversation on here a few yrs back as i too seen the info on an American tile forum , so I telephoned schluter uk and they told me that you just use what suits the substrate etc etc. The American site is geared towards American based adhesives

 

[Wesley]

I recently tried Ardex AF200 adhesive under the ditra matting onto concrete for the time. I found it simple to use, stayed “open” long enough to allow me to position the matting correctly and gave good results over a 30sqM floor

 

[Franer]

So got this e-mail back from Shluter UK this morning. You guys were correct, apologies for doubting. So any flexible mortar is fine.

Thank you for your email enquiry.

The words modified and unmodified mortars relates to products used in the U.S.A.

Schlüter®-DITRA 25 can be adhered to a suitable substrate using a cement based C2/C2F classification adhesive applied using a 4 x 4 mm notched trowel.

You can also use the same cement based adhesive above Schlüter®-DITRA 25 with a maximum bed of 10 mm.

Please see our installation guide linked below:

Schlüter®-DITRA 25

Should you require any further assistance, please do not hesitate to contact us.

Yours sincerely


Sarah Meller
Technical Services
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Schlüter-Systems Ltd | Units 3-5 Bardon 22 Industrial Estate
Beveridge Lane | Coalville | Leicestershire | LE67 1TE
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