Improper coverage on tile / Ditra not filled correctly

Photo 1

I am not writing this to tell you why your tile is cracking or why your grout is cracking – I have other posts that may tell you that. (Click on the pretty little links :D ) If you happen to have Schluter Ditra as your substrate, this post will tell you why either one of the above may be happening.

While Ditra is my preferred membrane for floor tile installation (as well as countertops and tub decks) it absolutely needs to be installed correctly. The two main techniques for this are fairly simple:

  • Make sure the cavities (waffles) are filled correctly
  • Install it over an approved substrate (and with the correct type of thinset mortar)

Improper coverage on tile / Ditra not filled correctly

Photo 2

There is a lot more to ditra than those two items but if either one is incorrect I can nearly guarantee a failure. See photos 1 and 2 there? The tile was cracked and it was a direct result of a) not getting the waffles filled correctly and b) improper coverage on the tile. Now b may be due to not backbuttering the tile, an improperly-sized trowel, letting the thinset skim over or set too long before installing the tile or simply incorrectly mixing the thinset. All three of those things will cause any tile installation to fail – whether you use ditra or not.

Not filling the waffles correctly, though, will cause the tile to not be fully supported and/or not ‘locking’ the tile into the ditra. Because it is not correctly locked into the ditra you will lose the mechanical bonding properties of ditra and you may as well install it directly to particle board at that point (That was sarcasm – don’t do that!). For more specifics about exactly how ditra works you can check out Provaflex vs. Ditra wherein I describe exactly how the mechanical bonding process works – and rant about a particular jackass. But the mechanical thing – that’s what you want to concentrate on. :D

You need to use the flat side of your trowel and spread thinset in every direction over the ditra to ensure that all the little waffles are full. Since the cavities are dovetailed (that means they go down and away from the opening) you need to ‘force’ thinset into the bottom corners of the cavities. Simply running the trowel over the ditra will not do this. Simply running the trowel over the ditra did that (photos 1 and 2).

Improper substrate for Ditra

Photo 3

Installing ditra over an approved substrate is much, much easier. In fact, nearly every bare substrate you find in a modern house would be considered an approved substrate – shiny linoleum is not one of them (Photo 3). While there are thinsets that ‘say’ they will bond to linoleum (and some of them will) apparently the jackass who installed that particular floor was not aware of that. :guedo:

See photo 4? I lifted that up with my pinkie – literally! It was not attached at all. He may have had correct coverage beneath the tile and all the little waffles filled – I have no idea. There was not enough stuck to get enough leverage to tear one off and find out.

Improper substrate for Ditra

Photo 4

Most any plywood (even osb :whistle: ) is an approved substrate for ditra. And  if you use a thinset approved for that substrate, there are no problems at all. Photos 3 and 4 had an unapproved substrate and, apparently, incorrect thinset (and a shitty tile job, but that’s a whole other post). It was nearly guaranteed to fail.

When you buy ditra for your installation every roll comes with a handy little instruction booklet. You can go to Schluter’s Ditra Page on their website and access the instruction booklet (This link is a PDF!). They even have a flash video about the proper installation technique. You can leave a comment below and ask. You can email me. You can send up smoke signals – I’ll answer.

Given the 17 ways to acquire correct ditra installation information above there is absolutely never a reason to do it incorrectly. Ditra, in my opinion, is the best membrane for most floor tile installations. The only time I’ve seen it fail is due to incorrect installation. And that isn’t just the common BS everyone accuses failures on. Me, personally, every one I’ve seen fail is incorrectly installed.

If you use ditra, and if you have an approved substrate, and if you have the correct thinset mortar, and if you fill the waffles correctly, and if you use the proper trowel and get proper coverage it will not fail. Yes, that’s a lot of ifs – when you read it. In practice it really is not that many things to get right. It’s just common sense, mostly.

So here’s one more if: If you have any questions at all about correctly installing ditra and using it for your tile installation please, for the love of all the marble in the Sistine Chapel, ask me below in the comments. I WILL answer you. I’m just super-cool like that 8)

{ 2505 comments… add one }

Leave a Comment

  • Todd

    Hi Roger,

    I recently had ~300 sq. ft of 12×12 tile installed over Ditra (concrete subfloor). When the job was done, about 1/4 of the tile had the dreaded hollow sound when tapped with a screwdriver, so I asked the installer to remove them (and the Ditra) to fix it. After removing the offending tiles, he says that the tile seemed to adhere well to the Ditra, but the Ditra didn’t adhere well to the subfloor (he thinks the thinset was mixed too dry). I want him to remove everything and do it again, since I don’t want a problem 3 years down the road (after his ‘warranty’ runs out). He says that isn’t necessary because even if the Ditra completely separates from the subfloor, the tile floor will still be sound – it will just be a floating floor.

    So my questions are:

    1. would a ‘floating floor’ really be as durable long-term as a properly adhered floor?

    2. How important is it to get good bonding between the subfloor and the Ditra?

    and

    3. Most importantly, if you were in my situation would you have him remove it all and do the whole thing over again?

    Thanks!

    • Roger

      Hi Todd,

      1. HELL NO!

      2. It is a key factor when using ditra as your membrane.

      3. I would fire his ass and hire someone who knew what they were doing. But I understand the money issue – yes, tell him to start over. It’s improperly installed, period. Ditra is a GREAT product, but it isn’t magic. It has to be installed correctly, and that means proper adhesion to the substrate.

  • Kane

    I have a customer who wants a fiberglass shower pan and ditra on the floors. Would I put the ditra over the entire floor and put the pan over that? Or install the pan first and butt the ditra to it?

    • Roger

      Hi Kane,

      Install the pan first, then butt the ditra to it.

  • Andrew

    I’m doing a small bathroom and was wondering, for proper coverage, if it would be ok to pour self leveler over the ditra heat to properly fill in and adhere to all the books and crannies while also sealing in the wires? I know the manual says there is no need because of the design, but I can’t find anywhere where it says to NOT do this. If I have the time to waste letting it cure, is there any harm in it?

    • Roger

      Hi Andrew,

      Yes you can. That will work just fine.

  • David

    Can you install the ditra over hardi backer board? If so which type of thin set should I use for under/over the ditra?

    • Roger

      Hi David,

      Yes, you can. Unmodified for both under and over ditra.

      • Kane

        I was told by Shluter to not do this. I don’t know if it’s a competition thing, and they don’t like to mention other product names, but that is what I was told. Actually, I don’t think I was told not to do it, just that they don’t have an opinion about it and won’t warrantee installation. Thinking about it, I think it has to do with the thinset. When installing Ditra over plywood you are to use a modified thinset – this is because the wood will flex. Since the wood is porous, it will allow the modified thinset to dry. Hardi will also flex, but a modified thinset won’t dry properly if used to attach Ditra to it, thus using a Non-modified is necessary. If I were to do it, I would put extra screws in the Hardi to help prevent flex and use the Unmodified.

        • Roger

          They actually do have an opinion about it – and it’s been the same in all three training classed I’ve been to throughout the country. Over backerboard you need unmodified thinset, period. I don’t know who you spoke with that was representing schluter but they are misinformed. :D

  • Chris

    I have read a million comments and it has gave me a great deal of knowledge about researching this product.

    I have a question. I have two small bathrooms that I would like to install marble tile (been purchased for years haha). I was about ready to buy cement board etc to start installing. I have a manufactured home on foundation and always hoped for a better installation method then I was informed of Ditra from others who did it. My question is……..will it work in my home on the plywood (should I screw the floor down anymore when I remove the vinyl tile? Also, do I have to change the way of using Ditra because I have marble tile?

    Any information is greatly appreciate.

    Chris

  • Tom

    I know this is definitely overkill, but would wire mesh and concrete be a suitable substrate for Ditra?

    • Roger

      Hi Tom,

      Concrete is just fine. Absolutely no reason at all for the wire mesh, why would you do that?

  • Zach

    I just installed the ditra membrane last night. I had some trouble mixing the thinset (my drill broke and I had to hand mix) but it was the versabond with polymer and I think that is the right kind. I also had trouble troweling it, it didn’t look exactly as it does in the YouTube vids. This morning I can see patterns of dark and light where the thinset adhered and did not. Most of the edges are adhered, and it seems to have set mostly, but not 100%. I also installed it over level, mostly clean OSB. Do you its okay to go ahead and install the tile? Or does it needs to be torn up and re-installed?

    • Roger

      Hi Zach,

      It should be fine as long as you can not grab it and pull it up off the floor. Ideally you should see uniform coverage, but it can be bonded and still look uneven. If you do find areas that pull up you can cut it out and replace just that piece.

  • Jan

    Hello Roger,
    How do I install the Ditra Heat system in my bathroom shower…Is there water proofing to be used on top of the electric cable…and how will they work?…Thanks!

    • Roger

      Hi Jan,

      It gets installed over your mud deck, then kerdi gets installed over it to waterproof everything. It works very well.

  • Greg

    Hi Roger,

    After months of reading about everything on your site and successfully finishing my shower, I’m now working on the heated bathroom floor. Heating cables are imbedded in modified thinset over OSB with no problems. I could kick myself for my mistake this morning – I thought the bag of thinset I used under the Ditra was unmodified, but it wasn’t (it was TEC 345 SturdiFlex). It’s curing as I type, and I’m nervous. Do I have to burn the house down now? Or will it cure, and just take longer? Not in a big rush to tile, I need a nap tomorrow anyway. Thanks!

    • Roger

      Hi Greg,

      Burn down the house? Probably not – how good is your insurance (it may be worth it… :D ).

      It will be just fine. Give it an extra day to cure and be sure not to turn on your heat prematurely (usually 7-14 days after tiling – the heating manual should tell you that).

  • Jim

    In Tile Tips for the Rich and Famous you mention leaving the back of the toilet uncaulked (thank you), but I have one related question. How do you prevent “stuff” from running down into the house instead of out the back? What seals the Ditra to the toilet drain pipe?

    • Roger

      Hi Jim,

      Not sure what type of ‘stuff’ is gonna run around to the back of the toilet, squeeze through that less than 1/16″ space and run into the house. No reason at all to seal the ditra to the toilet drain pipe – why would you want to do that? The wax gasket seals the toilet to the pipe.

      • Jim

        I am taking a cue from your tip about leaving caulk open at the back of the toilet to let stuff run out and be detected (page 18 0f 192, save thousands of potential damage).

        It sounds like “leave space in the caulk, but do not worry about sealing Ditra to pipe, – a failure rarely happens” – correct?

        • Roger

          It is simply a space to allow you to see if anything does ever happen. If your toilet develops a leak at the pipe or the wax ring seal fails, etc, water WILL get into your floor, there’s nothing you’re going to be able to do about that. However, if you leave that open area you will see water running out of it. If it is completely sealed you may not see it until the toilet falls through the floor. It is simply a failsafe to allow you to see if/when anything does fail.

  • dan

    info…

    this is my 5th tiling project, and by far my largest. roughly 300ft2.

    i’m considering using the ditra underlay for my 19×10′ kitchen, 8×3′ hallway, 6×8′ entry way. and also my 4×5′ bathroom.

    my subfloor is 5/8″ plywood on 14″ spaced joices. which appears to be better than schlepper’s requirements. it is in good condition and secure. i wouldn’t hesitate to lay backer board on it, but i’m uncertain about the ditra… it ‘feels’ less. :wtf:

    questions
    1. is subfloor prep for ditra comparable to backer board (was looking at permeable)?
    2. when watching the dirt video it appears i can tile immediately after laying the ditra?

    • Roger

      Hi Dan,

      1. It is a bit more prep since you have to remove anything that will compromise the bond of thinset to the substrate.
      2. Yes, you can tile immediately.

      Ditra, once tiled, is actually a MUCH better system and much more appropriate to normal structural movement and compensating for it.

  • Andrew

    So I have recently had a flooring contractor install Schluter Ditra heat system in my kitchen (complete remodel). I believe that they used the correct materials as he discussed with me the theory behind why you have to use the specific types of thinset, etc. with Schluter ditra system. Approximately a week after the installation, I noticed that there are several areas where the grout has cracked and or crumbling. THe contractor believes that this is a grout issue and has contacted the rep. I am not sure what the issue might be, but there are also areas where the grout is light in color and dark in color, like it never dried and it has been 3 weeks. It is dry to the touch, but it just never lightened up. Could this be a grout issue when the grout is cracking all over? or is it more likely that this is an installation problem?

    • Roger

      Hi Andrew,

      It may be a grout issue. I wold wait and see what the rep has to say, he would have the best answer for you.

  • Mike c

    Hi. So my installers laid one piece of ditra today before ru ning out of time and leaving for the day. I goofed and walked on it. You can see indentations in the mat. will he have to rip it up tomorrow or can he even them out when laying the unmodified thinset when laying the tiles? The floor was flat and level before the ditra was installed. I think by stepping on it before completely dry some of the thinset just shifted.

    • Roger

      Hi Mike,

      They can compensate for that as they install the tile.

  • Tom

    Hello Mr Elf.
    I am a tradesmen but new to tiling. I’m redoing my bathroom and used dirta on the floor. I was about to mix up mortar for setting tile when I realized I used the unmodified mortar on the plywood to set the dirta.

    • Roger

      Hi Tom,

      That may last and it may not. My money is on not. Unfortunately the only way to fix it is to remove and replace the ditra with modified thinset.

  • Ryan

    Hi Roger,

    I installed some Ditra over plywood yesterday — total beginner. I think I didn’t make the thinset runny enough. It’s set up mostly now, and around a few of the edges (floor air vent, for instance), I can lift up the ditra without a terrible amount of effort. Should I treat it as if those areas did not get proper adhesion? Cut them out and replace them? I’ve got spare thinset and Ditra, and I’ve got time. Just curious if this is something to be concerned with or if I should move forward to laying tile.

    Thanks for the blog, it’s fantastic.

    • Ryan

      One other thing: the places where I was on my hands and knees seems to have left some dimples. I worked hard with a pool trowel to smooth it back out, but it was not entirely effective. Should I move forward or instead should I cut out the dimpled areas and patch?

      • Roger

        The dimpled areas are fine. They won’t affect anything.

    • Roger

      Hi Ryan,

      Stop doing that! Seriously, stop it. :D

      Nothing at all on your floor will ever ‘pull up’ your ditra. Once it’s fully cured and you can do that then yes, cut it out and replace it.

  • Scott Brueske

    Hi Roger

    I am using Ditra for the first time and am laying 1ft x 2ft Travertine. The Ditraset thinset bag says to use a 1/2 x 1/2 square trowel. when laying the tile. This seems huge. Is this right? do I need that large of a trowel for the larger tiles? That seems like a lot of thinset.

    • Roger

      Hi Scott,

      Normally you don’t need one that large with most natural stone (it’s normally flat). I use a 3/8″ for most large tile.

  • David

    Hi Roger,

    I pulled up old vinyl in my bathroom. Can I install Ditra on top of what’s left of the paper/glue (very thin layer over nearly the entire floor space) from that old flooring?

    David

    PS Your website is great – you’ve walked me through many of the remodel steps so far, and everything seems to be going great! :)

    • Roger

      Hi David,

      You want to remove all of that. I used to go over the stuff that was nearly impossible to get up, until I ended up eating a job because their toilet leaked and all that glue let go. They had a floating tile floor when it was done. :D Most of that glue is water-soluble.

  • Kevin

    Hi Roger,

    I’ve got an odd room we are planning to tile, and wanted to ask about DITRA over mixed substrates. The house is slab on grade, but sometime during the past ~70 years, someone added a section on piers off the kitchen. The substrate in that area (about 7′ x 12′) is 3/4″ OSB, and I’m open to replacing that if necessary. Previously, the whole area (both the slab on grade and the OSB substrate) were covered with linolium, then later with 12″x12″ laminate, which is now badly cracked where the substrate transitions. We would like to replace with basic ceramic 12 x 12 . My questions are:

    1) Should we change the OSB to another substrate for better / longer lasting end results?

    2) Can DITRA be used as a decoupling membrane over these various substrates (assuming appropriate application of modified and unmodified thinset per the DITRA specs)? I’ve had it recommended to me by a friend who is a competent general handyman, but would prefer to ask a flooring guy, as I don’t want to jump in if there are doubts about the durability of the end product.

    3) Anything else I should be considering?

    Thanks -Kevin

    • Roger

      Hi Kevin,

      Yes, you can use ditra as your uncoupling membrane. You will, however, need to have a soft joint over the transition.

      1. You can replace the osb with deck mud, but you’ll still need the soft joint.
      2. Yes.
      3. Using the ditra as an uncoupling membrane over different substrates is perfectly fine. You do need to transition between them with a soft joint, as the two different substrates will expand and contract at different rates and may crack grout and/or tile if the movement is not compensated for.

      • Kevin

        Thanks for the info, the soft joint was news to me – you’ve saved me a lot of headaches. I see mentioned in your soft joint article that over concrete expansion joints, the soft joint can be offset up to 6 inches depending on the membrane used. Would this also apply over the substrate transition?

        If so, should the soft joint be placed on the wood side of the transition or the concrete side, or does it matter? Or should I set my field in order to place the soft joint directly over the transition?

        • Roger

          Ideally you want the soft joint directly over the transition. If you do span it with a tile you need a soft joint on BOTH sides of that tile, not just on one.

  • loti

    Dear floor elf,
    we are almost finished installing ditra across 750 sq ft, the space includes kitchen, living room, dining area. We laid out the ditra to have as few seams as possible so we have 5 continuos lengths which are notched in places to accomodate closets and short walls We tore out old tile, and carpeting, filled in holes in the concrete, and sanded down high spots. To the ditra installation, the night before the concrete was mopped with water only to get rid of dust, as well as vacuumed. The day of the install we pre moistened the concrete before trowelIng the thin set the thin set was different consistencies from runner to thicker but all held a “v”. After we ran through the two 50 lb bags of plain thin set from the tile distributor we bought Custom brand non modified from HD. There are areas that look like they’re not sticking, it hasn’t been 24 hours yet but if we see that there are intermittent areas where it’s lifting, can we slice through the Ditra and just repair those areas (are seams an issue?, or do we have to roll up the entire length and scrape up the thin set and reapply?) Can we even reuse the Ditra once it’s pulled up? One thing is for sure, we are taking a break for a week before going forward. I’d much rather deal with the issue now, then after the tile is down.

    Also when we are ready to I stall tile should the thin set be running runner for the top of the Ditra installation?
    thank you in advance for your help

    Here is what it looks like now, once we’re back in the house I’ll send pics of the Lifted areas

    https://flic.kr/p/r7ECm3

    • Roger

      Hi Loti,

      You can cut and patch ditra wherever you need to. It is normally just an issue when the fleece on the bottom is not embedded, that could be because the thinset skimmed over before it got covered or simply not pressing down enough to embed it well. If, when you cut it out, the fleece does not tear off of the back you can reuse it. If the fleece tears off the back – it was fine, you shouldn’t have ripped it up. :D Make sure it’s actually lifting off the floor before cutting it out.

      Mix your thinset normally for the tile installation, not runnier.

      • loti

        I’ve heard back from my brother, he’s gone back to check the installation, and he counts 20 areas where the ditra has popped up. So, after curing it managed to get worse. A hammer rental is in my future, I will take pics and post them as a lesson on what not to do. In the meantime, I’m picking up some Keri bond tomorrow, we have a week off next week to tackle it again. If at first….

      • loti

        Pic of heart wrenching defeat I wonder if we can just buff it a and call it concrete
        None of the Ditra stuck Any suggestions on how to scrape up the thin set?https://flic.kr/p/qxAW2p

        • Roger

          Ughhh. Sorry you’re dealing with that, it sucks. Go rent a 7″ grinder with a scarifying wheel, it’s the quickest. You can scrape it up with a floor scraper, but it takes forever and sucks more. Mix your thinset A LOT thinner next time, so it barely holds a notch.

          • loti

            Thank you Roger.
            I’LL let you know how it goes

          • loti

            Roger, Roger, Roger!!!
            I have to tell you, my partner in crime resisted renting a grinder. So we rented the hammer again, you are right, it was not good.

            https://flic.kr/p/rgZaBP

            So we went back to HD and they didn’t have the 7″ grinder with a scarifying wheel. They did have a 10″ grinder, with a vacuum attachment, and I forget which wheel they gave us, will have to check the receipt if you are interested.

            https://flic.kr/p/rAd4GJ

            I loved it, 45 minutes later and we are thin set clear.

            https://flic.kr/p/qDwp7a

            Fantastic!! I loved that grinder and was looking for other things to grind. We had to be careful not to stay in one spot the grinder was pretty strong.
            Thank you so much, I’ll have a look at your instructions for upload when we have the floor down.
            :dance: :dance:

  • brad

    Can I lay 1/8 ditra right over 3/4 plank pine boards for underlayment?

    • Roger

      Hi Brad,

      No, you need a 1/2″ layer of plywood over the planks.

      • Ann

        Dear Roger,
        I’m sorry for responding in the wrong place on your website, but I’ve pasted this question several times, and haven’t heard back from you. I’m not certain what I’m doing wrong. Hopefully, I’m better at tile than technology : ) Anyway, my question is listed below….

        We are doing our umpteenth tile installation. Or, at least it seems that way. Our oldest son was over last night, and, as usual, was giving advice to us on what we are doing WRONG on our tile installation plans. Since there is at least a small chance he is correct, I thought I’d ask your opinion.

        We are planning to put 21″ x 21″ tiles in our basement bathroom floor. They are very high quality, textured-type commercial tiles. He stated that tiles installed on concrete will always, always crack, and that we should go with smaller tiles to prevent this. (He worked at one time for a “high-end” remodeler, so he has some experience in these matters.)

        Our first thought is that if the tiles are installed correctly, with actual thin-set under the entire tile, it shouldn’t crack. But, what do we know? We’re just the old, feeble-minded parents. Should we play it safe and put Ditra over the concrete and under the tile? Go with smaller tiles? Give up and use carpeting?

        We couldn’t have done the tile projects we’ve already finished without you….many thanks,
        Ann

        • Roger

          Hi Ann,

          There is no ‘wrong place’ on my website. But I did respond to one of your posts (the others were deleted) five days ago right HERE. I get all the questions, and answer them. You should have received an email notifying you that I answered it, it’s likely in your spam folder. The only thing you’re doing wrong is repeatedly posting the same question. Stop that. :D

  • matt

    Hi roger,
    I have done many tile jobs, but trying dit ra for the first time. A friend of mine suggests I fill the cavaties, let cure 24 hours then notch and lay tile. He is an experienced tiler specifically with ditra and I’m not doubting his word lol but I have not seen or heard anybody suggest this via how to videos etc… have you ever heard of this method? And what are your thoughts?

    • Roger

      Hi Matt,

      Yes, I prefill ditra often. And no, you won’t find the method stated online. :D It works just fine.

  • Ann

    Roger,
    Just installed a porcelain tile floor in a heavily traveled room with the long tiles that look like wood. I had a wood substrate, used modified mortar, then the ditra (not XL). Waited 24 hours and put unmodified mortar AND thought I covered all the little squares going several directions with the trowel. Here’s the issues. This was my first ‘big’ tile job as I’ve usually just done little back splashes, and they seemed easy and ‘stuck’ so thought I’d give this a try. (Too old to have even contemplated this task, but alas,… here I am) Obviously I didn’t understand the value of a trowel and the benefits of the sizes. I put too much modified mortar under the ditra in the beginning so lessened as I went. Noticed occasional ‘hump’ in the ditra. And appears it may have happened in other spots. Getting ready to do grout tomorrow (time line for furniture to be back in room), and after 24 hours of tile being on floor found one that evidently didn’t stick. Right in the middle of the floor where traffic will be of course. So I’ve scraped all the old mortar out and redid it with extra mortar because I’ve noticed there were some spots without mortar showing on the tile. Now I’m near panicked how many more may break loose?? I’ve walked all over it listening for any sound of giving. Tried the tapping for dull sounds and occasionally I hear it, but not sure as tile ‘seems’ set and became a daunting task. I can’t find anywhere online about too much mortar under the ditra causing uneven floor, (I definitely have some lips but conceding on those as not the worse thing). Question is: If others were like this one, would they have come up by now with me walking all over them and scraping the edges for grout? And, IF worse comes to worse and they break or lift, could should I cut through ditra to modified mortar and build back in layers?

    • Roger

      Hi Ann,

      It may very well happen to only one tile in an installation. If everything else seems solid go ahead and finish it. If another does happen to come up, cut all the way through the ditra and reinstall in layers as you’ve stated.

  • ron

    thanks nick I didn’t know that guess i’ll have to read a little more….ron

    • Roger

      Please use the ‘reply’ link when replying to someone, something clearly stated above the box in which you typed this. I have over 30,000 comments here (seriously), when the reply link isn’t used they are not threaded (one following the comment thus making it a ‘reply’) and it looks like random people talking to themselves.

      I’m the only one allowed to do that here! :D

  • Nick

    Hey Ron,
    I am not a pro but I read the Ditra installation manual on the schluter site because I too am using it…and I think 2×2 is the smallest you can apply to Ditra.
    Fyi …and sorry if I am hijacking.

    • Roger

      Hi Nick,

      I have no problem with hijacking with correct information – and yours is, thank you. It is more effective, however, if you use the ‘reply’ link in the comment, that way the author of the comment gets a notification emailed directly to them. Thanks for your help, I’ll take all I can get! :D

  • ron

    hi roger,
    im installing 1×1’s over my ditra floor is it necessary to back butter them., and should I do the same for the rest of the bathroom…all the tiles are 1×1’s in a mosaic pattern
    thanks ron

    • Roger

      Hi Ron,

      No, 1×1 mosaics do not require backbuttering. However, 2×2 is the smallest tile you should install over ditra.