Can you use modified thin set with Kerdi and Ditra?: Yes if you use Ardex

[Eurob]

5) Nanolight 72h to 96h ( 4 days ) mark .

Possible signs of cure -- 3/4'' around (under ) the perimeter of the glass with no visible signs of change of humidity levels . The color stays uniform through out the curing process , which makes it hard to see changes in the humidity levels . It may also cure uniformly -- loosing humidity in a uniform pattern -- , but it is doubtful the cure is complete .

 

[Eurob]

6) Ultralite 72h to 96h ( 4 days ) mark .

Possible signs of cure -- 3/4'' around (under ) the perimeter of the glass with no visible signs of change of humidity levels . The color stays uniform through out the curing process , which makes it hard to see changes in the humidity levels . It may also cure uniformly -- loosing humidity in a uniform pattern -- , but it is doubtful the cure is complete .

 

[Sponsor]

 

[Eurob]

7 ) X5 72h to 96h ( 4 days ) mark .

Sign of cure of about 15% more through out the area under the glass . Moisture still present , cure is still in progress .

 

[Eurob]

8) X77 72h to 96h ( 4 days ) mark .

Sign of cure of about 15% more through out the area under the glass . Moisture still present , cure is still in progress .

 

[Eurob]

If I would have to resume the 4 days curing process -- do not forget these are the toughest conditions of testing , no air present , a 3/32 thick mortar layer , 100% coverage , etc. --- I would say .....

1) GraniRapid didn't do what is supposed to do . Instead of 6 hours it took 60 hours with a question mark on cure still in progress .

Definitely needs more testing to see the real cure times .


2) Kerabond& Keralastic did exactly what it does best . Reliable and slow to cure , but it does it in decent times . Great coverage , a very good premium exterior mortar . Never failed me in over 20 years .


3) 254P did also great . Great coverage , slow cure , I like the uniform curing pattern happening under the glass . Good signs of a premium mortar .


4) 255M it is a strange mortar . I do not like how the humidity is dispersed in the curing process . I really hope that at the end of 7 days , the humidity is gone . Not a mortar I would use .


5) Nanolight , this mortar is hard to read . I am still not sure if the humidity is present or not under the glass , but it looks like it has signs of cure 3/4 deep around the perimeter , under the glass .


6) Ultralite , this mortar is also hard to read . I am still not sure if the humidity is present or not under the glass , but it looks like it has signs of cure 3/4 deep around the perimeter , under the glass .


7) X5 , this mortar has a nice texture , nice coverage , but the curing process is quite strange . It does a lot in the first 24 - 60 hours , but then it kinda slows down quite much . I was sure it would be done by now since the presence of the air is not required , but maybe it has other factors happening which slowed the progress .


8) X 77 , this mortar also has a nice texture and great coverage , but as the X5 , the curing process is similar . Since it is few levels more modified than the X5 , you would expect more interference or longer cure times .
I observed a slower rate of curing going on in the first 24-60 hours , but then it caught up with X5 and I can say they are quite similar in humidity levels at this point .



Alright , that's it for now .

 

[Jadnashua]

Some modified mortars attain their strength without drying. So, the fact that it still appears wet may not be an issue. It is a very much bigger issue with 'conventional' latex modifiers. This is also why Schluter will let you use this class of mortar on their membranes if you ask them. Any of these specialized materials beyond their use by date is questionable, and may not be representative.

Have you checked with Mapei's tech services? They may have some thoughts pertinent to this.

 

[Eurob]

The actual cement cures in a pretty linear timeframe. But, in a modified, the modifiers are acting like the insulation on wire, helping to support and protect those curing cement crystals. But, since they are further apart when you throw the modifier in, and remain soft until they dry out, it's more like the cured material is suspended almost like the sand, and not actually holding onto things well. The modifiers do act somewhat like a glue, and that is creating some of the bond, but the whole assembly is soft, and the modifiers can be washed away if exposed to liquid water until they have dried or polymerized (depending on the type of modifier). There are some modifiers that can sufficiently harden without drying.

Some modified mortars attain their strength without drying. So, the fact that it still appears wet may not be an issue. It is a very much bigger issue with 'conventional' latex modifiers.

Those 2 are kinda like the same , but they make no sense . What are you talking about ???

ON one hand the modifiers are helping , supporting and protecting , but then the cement crystals are far apart and with the modifier in , they remain soft ( not helped ) , cured material not actually holding onto things well ( not supported ) and they can be washed away by liquid water ( not protected ) .

Beats me , must be something wrong there , like saying you cannot use a modified with Kerdi , but the rapid ones are allowed . Can't have it both ways .

This is also why Schluter will let you use this class of mortar on their membranes if you ask them.

So if I don't ask them , they will not ? Tell me this , how many modified mortars Schluter let you use with their membrane ?

Have you checked with Mapei's tech services? They may have some thoughts pertinent to this.

I do not need thoughts , I need answers .

Why to disturb them -- tech services -- ? I want them to be relaxed . Thanks God , it is not a real project .

The best before date shouldn't impact a mortar in such a way .

 

[Jadnashua]

Some modifiers, acrylic ones for example, do not need to dry to get their ultimate strength. A modifier that can 'cure' or 'set' whatever you want to call it while still wet can be used over Schluter's products if you ask them, and because they do their thing in a known timeframe, like a dryset, won't compromise things. A modified that needs to dry (most, if not all latex modified mortars) DO need to dry to provide their full support and can be damaged if loaded, or have the modifiers wash away if exposed to lots of water before they get their initial drying/cure/set and is NOT approved for use over their membranes. As your testing shows, eventually, things do dry out, but most people will not want to wait that long, thus Schluter's recommendations.

If you think about it...if your modifier is wrapped around you cement, the actual cement particles will be further apart than if there was no modifier there. Since the cement could reach its full crystalline size before the modifier dries to support it, if the modifier gets washed away, the bits can literally fall apart.

Cement cures once it gets wet. You can mix in some inhibitors to slow it down (most have some, some have a lot, hydraulic cement has essentially none), but once it starts, it is a known timeframe. Cement itself cures just fine while wet. And, when the mortar is mixed properly (there's always an excess moisture to allow you to spread it), if you keep it moist, the cement can hydrate to its maximum capacity - effectively becoming as strong as possible with that particular mix. Do not confuse keeping things moist with the design water content with overwatering, which will make the mix weak.

 

[Eurob]

So much words , without nothing concrete . You must be like an unmodified one .

The modified mortars are engineered to do what they are suppose to do . Cure and provide characteristics found into the data sheet .

Why do you keep avoiding the real questions ? So.....

WHAT are the modified mortars recommended by Schluter over their membranes ? You can give us 2 mortars per manufacture -- Mapei , Laticrete , CBP , TEC , Ardex , -- , to name few .

Stop interfering if you are here to give us only one biased opinion -- Schluter's one -- .

 

[JohnfrWhipple]

....When I get my testing factory in a '' better shape '' , I will run plenty of tests .

Thank You.

Let me know if you would like me to clone any of your specific tests.

 

[JohnfrWhipple]

....WHAT are the modified mortars recommended by Schluter over their membranes ? You can give us 2 mortars per manufacture -- Mapei , Laticrete , CBP , TEC , Ardex , -- , to name few .....

A technical director of one company told me one day that Grani Rapid without the proper liquid was approved.... I asked this of the Mapei folks and was told that is not allowed. I was confused over the conflicting reports.

I asked Ardex and they told me X5 is fine. Sent me a copy of their warranty too. 10 years. About 6 months after Ardex did that Schluter bumped their 5 year to a 10 year to march Ardex's.

A schluter rep told me Ardex and Kinsel have better technology. But did not say what product.

Once you use a modified you have left any of Schuter's printed recommendations so any modified thin-set is a deal breaker. You must get written permission from Schluter's head office for any modified thin-set use. You need a site visit from a rep. You need to know the framers home address and name of the subfloor and walls. And also the plumbers name and address.

Or - you can just use Ardex. Email ardex and get a no hassle ten year warranty.

Like I said before. If you want too use modified thin-sets with Schluter you can. BUT ONLF IF THEY ARE MADE BY ARDEX AND ARE THE ONES THEY RECOMMEND. X32 for example is not rated to install Kerdr or Ditra....

 

[Eurob]

Thanks John for the clarification .

After all the thread is about Ardex mortars over Schluter membranes ....... All it points towards -- X5 & X77 -- work and cure under the glass and Kerdi sandwich.

 

[JohnfrWhipple]

Thanks John for the clarification .

After all the thread is about Ardex mortars over Schluter membranes ....... All it points towards -- X5 & X77 -- work and cure under the glass and Kerdi sandwich.

No shocker Roberto. Remember Ardex makes 8+9 for Schluter and Schluter calls is Kerdi Coll.

They are two German companies.

Hiding this info is not about weather it works or not. It is about not pissing off Laticrete and Mapei. Those two companies sponsor the other forum. Laticrete and Mapei don't offer up any modified thin-set warranty with Schluter. Neither does custom to my knowledge.

Info online is often influenced by the all mighty dollar. Why promote Ardex when Laticrete pays the bills. Why use Kerdi in the first place?

Why not use Hydro Ban Sheet Membrane instead? Or Noble's membrane's? Then you have not so many restrictions - and you don't need the name and address of every person working on the project.....

When was the last time a builder gave you his framer's home address and name? LOL I dare you to ask one and see what the guy tells you....

It is however a requirement of some warranties.....

 

[Eurob]

I found it sufficient to say that modified mortars are recommended for water and vapor proof sheet membranes.

Laticrete does it , Mapei does it , CBP does it and on and on and on. But Schluter doesn't officially.

And Jim on top of it is here explaining to us how bad it is to use them. From what I know of , Schluter doesn't make mortars , grout , epoxies , but sheet membranes.

I would say that mortar manufacturers know better. We just need mortars which cure in a specific time frame and are reliable from batch to batch .

It is why the one time test should be done at random times.

 

[ShowerDude]

WOW ! framers address !!!!! more opt outs for the mfg.

John, you mentioned an ardex wrrty, but you dont really buy into warrantys do you? is your current steam shower covered under warrantys?

Roberto, .....very interesting and useful garage data. do you have access to CBP Speedset? now you have me thinking.

 

[Jadnashua]

Since Schluter does NOT make mortars, and mortar companies do NOT announce that 'oh, by the way, we changed the product somewhat, and it will no longer work properly with your product', and Schluter does not test their product with all sorts of different mortars...why would they recommend one? DitraSet is not made by them, but is made to their specs. You do not have to use that to gain the warranty. They know that any premium unmodified mortar works, and there is very little variability between those products (don't try to use the price leader in that category, it is a lot harder to use - often grainier, less cement, less margin for error than a premium version). There's a HUGE difference in the technology of modified mortars. A dryset is essentially Portland cement and sand or other similar aggregate with maybe a retardant in it so it has longer working time. A modified mortar is a much more complex mix of components.

Essentially, ANY modified mortar that is designed to allow its modifiers to become stable IN THE PRESENCE OF EXCESS WATER will work. Check with the manufacturer to qualify the product for those conditions. Generally, this is limited to rapid set mortars. The whole thing on modified mortars is, some will get the idea that ANY one will work, and as you can see, that's not the case. And, what works today, may not work tomorrow if they change the formula.

Mapei made a big point of that in their workshop earlier this year...and is one reason why manufacturers are sometimes reluctant to specify another company's products with theirs. They can test today, and it works, but tomorrow, the 'new and improved' version shows up on the marketplace, and it no longer does. Nobody can afford to continually test each new manufacturer's product as it comes out to verify compatibility.

The basic premise on Schluter's instructions is: a dryset provides more than adequate bond strength with their products as evidenced through nearly 30-years of field experience. A modified mortar can take many days to become stable when used with a nearly impervious tile. If that tile is subject to any stress before it is well bonded, that bond can fail. How long are you willing to wait? A dryset mortar will 'cook off' in a known timeframe, and that can be specified easily in their instructions on when you can proceed with the build.

Porcelain and glass tile has been used on both walls and floors for centuries...modified thinsets came out in the 1950's. A membrane approximates the functionality of the old time construction methods. A dryset works, and its functional equivalent has worked for centuries in much less pure, controlled forms.

So, if you feel you must use a modified with these membranes, verify from the manufacturer that they become stable while still wet, and Schluter will allow you to use them and attain their warranty. That will almost always require a rapid setting mortar. Otherwise, you're at risk.

 

[Eurob]

Roberto, .....very interesting and useful garage data. do you have access to CBP Speedset? now you have me thinking.

I think so , RSCB .

No access to CBP Speedset , but I can look for it . I know I can get it somewhere locally .

For now a new GR kit is ready for future testing .

 

[Eurob]

Regarding the Orange poster , more empty words . No real answers .

Feel free to use a super absorptive mortar in between 2 non absorptive layers -- porcelain tile and sheet membrane . I am sure the mortar will act like a sponge once it is cured .

 

[Jadnashua]

You guys just don't get it! There are mortars that are designed to reach their design strength even if they can't dry. Almost any rapid setting mortar works that way. The goal with a membrane is to ensure you have a good bond before you continue. That's exactly what rapid setting mortars are designed to do. A dryset mortar does as well, and is less expensive, and easier to work with. With a latex based modified, you may need to wait for many days, or your job is at risk...how much, just depends. A 24x24" porcelain tile is a much bigger difference than a 2x2 mosaic.

A mortar that uses a latex based modifier, at least the vast majority, DOES need to dry to achieve its design strength. To some people, modified is modified, and they do not make any distinction. It's much easier to just say a premium unmodified and for most jobs, it works just fine.

What your testing is showing is what the TCNA has been saying for years...a latex based modified mortar can take extended time to dry and reach design strength when used in between a waterproof membrane and an impervious tile. What your test is not showing is what actual strength in both compressive, shear, or tensile strength the mortar is achieving...on a rapid setting one, drying isn't important...it will dry out eventually under most conditions, and even if it doesn't, it doesn't affect the bond strength. That's not true when latex modifiers are in the picture without some additional chemical magic in the mix to compensate.

Simple answer, any mortar will work over membranes IF you are prepared to wait for it to dry out. This can take many days to actual months. A rapid set mortar will work in a reasonable timeframe as will an unmodified.

The reason Ardex 8+9 works is that it is a rapid setting product. There are other rapid setting products that will work. Whether you need them (Schluter says you don't) is a personal decision.

 

[Eurob]

It seems that you are here for 2 reasons

To sell the orange stuff and

To interfere and detour the discussion towards third parties .

You are not listening to what we are saying , not answering to specific questions , not doing more than repeating over and over some prepped literature and there is only one way to deal with it

I tried , John , but I didn't listen . Now it is time .