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My husband and I are doing our own bathroom remodel before we sell our house. We would have been on schedule to finish the bathroom by the end of this weekend. We installed ceramic tile over the Ditra membrane using some premixed mortar that he bought. 90% of the way through he ran out of the premixed stuff and started using a standard powder thin-set mix. Two days later the rows that he used the powder thin-set are set - in fact they were pretty stable 24 hours after the install. BUT - the majority of the floor is still not set. I double checked the bucket of the premixed stuff for curing times and noticed it says, “Do not use with….polyethylene membranes or other membranes” and Ditra’s website says, “Schluter®-DITRA is a polyethylene membrane.” The bucket also says non-porous substrates may extend curing time. :cursing:

My husband wants to wait it out and see if it sets. 8| He thinks the mention of non-porous substrates extending curing time will somehow cancel out the fact that it also says not to use it on polyethylene membranes, or any membrane for that matter . I want to remove the tiles that haven't set, clean everything off and start over with the right product.

HELP! What do we do?
 

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YEP.... You used the wrong stuff...

I don't know if it will ever set satisfactorily... I've never done that.....maybe someone will know.

But I'd act quickly probably, and maybe you can pull that tile up still and maybe save part of the job..... there are different mastics on the market...I don't know if you can clean up you tile and membrane and reuse it... sorry not sure.

Maybe you can try one small inconspicuous corner and see if you can.
 

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Thanks for the reply. My husband did not want to hear that we needed to pull it up and do it over. Frankly, I didn't want to hear it either...but I figured it was likely inevitable. I will try and pull some up today and see how it goes. At this point the mortar is still pretty mushy. I took a screwdriver and scraped it in the grout line between two tiles and what I got up was still very moist. Any thoughts on how to go about removing it without breaking tiles?
 

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We installed ceramic tile over the Ditra membrane using some premixed mortar that he bought.
The tub likely does not say "mortar". Mortar does not "dry". Mortar is rather like concrete, that has a chemical reaction with water, and "cures" solid. You can soak cured mortar in water as long as you want, it will not dissolve, it has cured.

Sounds like the first stuff is an adhesive that dries by evaporation.
 

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Yeah, it says 'mortar' on the tub but it was still the wrong stuff. Anything pre-mixed cannot be thinset, as SPS said, since thinset is cement-based and starts to cure as soon as water hits it.
 

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Again, thank you? I think I established that the wrong product was used in the initial post. Do you have anything constructive to add? I did ask questions in my previous posts. Questions that neither you nor SPS has seemed to answer or attempt to answer....
 

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Before you wholesale remove that tile
I believe you should be prepared for either:
soak/cleaning tile backs & replacing floor membrane or
attempting to clean/save membrane & possibly trashing tile...
due to that adhesive may set up quick once allowed to breath
so Does container indicate what product(s) to use to clean up this adhesive?

Peace
 
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DR. P has a good idea, as, if it turns out cleanable, it is likely you would want to immediately clean as you go.

This does not necessarily help, but I'm pretty surprized that there is not better disclosure on that tub..... I'm not familiar with that ANSI-spec they refer to, but I've never known a mastic that can be used in non-porus conditions.

But the strange thing is that TEC is a good brand, and I'm surprized they would mis-represent something.

I would call TEC right away (before tear-up) and confirm that won't eventually set. I told you early it was wrong stuff (what I really meant was I'd never heard of a mastic that would work in that application).... but new products are invented every day.

Hope springs eternal in the human heart.... Good luck

EDIT: Oh sorry.... I just noticed that you did see the disclosure on the tub..Sorry
 

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Dr. P, thank you so much for your helpful response. Unfortunately, it does not say anywhere on the tub what to use to clean up. I have two plastic tubs I filled partially with water and I plan on using them to soak any excess product and remove it. Thanks for your thoughts!
 

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MTN, thanks for the helpful response. I did call both Schluter and TEC. They both said the same thing, it needs to be removed. The rep at Schluter believes if I can clean up the membrane enough without damaging it I should be able to reuse it. Here goes nothing....
 

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I don't know the TEC "Mortor" mastic (and sorta still think it is a mis-representation in title)..... BUT

...Maybe ya get lucky:smile::wink2:

I love using mastic (on kitchen dry backsplashes) and the stuff I use cleans up pretty easily with just water...

Good going.... just for education... let us know how well it cleans off the Ditra...

(Might be tricky breaking the suction bond without hurting the Ditra...?)
 

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What was used to set the Ditra? (Hopefully not the pre-mixed stuff. Should be thinset, modified if installed over plywood/OSB, and unmodified if over concrete.)

For setting over the Ditra, Schluter calls for an unmodified thinset. (Although this would be a less serious error than using the pre-mixed, and would probably be okay if you gave it an extended dry time.)

Thinset doesn't actually bond to the Ditra, its mechanically attached through the dovetails of the "waffles." As long as you can get enough of the pre-mix off the Ditra that the dovetail profile is maintained, I'd think you'd be good to go over it again with unmodified thinset.
 

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I am not quite sure of your intention with this reply, but thank you for your helpful addition to this thread?
Just thought you, and others, may be interested in understanding the difference.

Lots of people read these threads. Could be 5 years from now, somebody researching their first tile job comes across this thread. And they learn also, that just because the name-brand uses the word "mortar", the fine print may show that its is in fact different, and has limitations on where it can be used.

Sorry if I was not able to provide a solution to your problem.
 

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Dear friend, thanks for sharing your post with us. I know sometimes when there are mistakes made , it makes you feel vulnerable. So I say thanks you for having the courage to reach out in this post.

I am very familiar with Schluter Systems. I to have make some mistakes and I learned a very good rule of thumb. If you are going to spend the money on good high end product , try and go strictly by that companies recommendations for the whole install. Meaning use their specific thin set for that application. You will spend a little more up front but it is worth your investment. Take care and use this as a learning process and don't let these bumps in the road discourage you from future DIY projects. Because they can be a lot of fun and very satisfying.

Johnny
 

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UPDATE: I was able to get the tiles up fairly easily with a stiff putty knife. I removed everything one row at a time and very methodically scraped the backs of the tiles removing as much excess "mortar" as I could, then placed each tile in a plastic storage tote filled partially with warm water. I then removed as much of the the excess "mortar" from the membrane as possible. Following this I went back to the tiles and scrubbed the backs with a plastic bristle scrub brush, towel-dried each tile, then stacked them in order off to the side and continued this process. It took three hours, but I was able to salvage all of the tiles as well as the membrane without issue. I re-tiled the floor with the appropriate mortar the next day. A day later we grouted. The bathroom is really coming together (finally!).

Thank you for all of the advice and helpful tips.:biggrin2:
 

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Sorry, you definitely did not want to use that stuff! You can definitely get away with using a modified thinset mortar over Ditra, since it will set hard even if it takes months to dry (drying is not necessary for setting, but with modified thinset it has to dry to reach full strength - half strength is plenty strong enough though for now). The premixed stuff has to dry to set, unlike standard mortars.

It will set eventually, just depends on how many weeks you can wait.

As far as going back over the Ditra, you don't have to get it out of the waffle holes. But you do need to let it dry. Then hopefully the new thinset has to adhere to the old "mortar" in the waffle holes, which it should (nothing adheres well to the Ditra itself, which is fine.)
 
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