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 
) 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)
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.
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).
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. 
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.
Photo 4
Most any plywood (even osb 
) 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 
I’m installing tiles in my bathroom. I’m considering using ditra and laying it over plywood. My question is – would this last? Wouldn’t ditra separate from plywood after years?
Thanks.
Hi Tom,
Hell, I hope not. I’ve been doing it for about fifteen years.
Provided you use a good modified thinset the ditra will last until you want to remove it.
Hi Roger, thank you for providing such a great resource! In our new build, our tile installer is planning to use SLC over the ditra and then a layer of unmodified thinset over the SLC. I know Schulter instructions say not to do this. What are your thoughts?
Hi Shannon,
It will work, but why??? And you’ll lose any warranty you have. And modified thinset should be used over slc. If he needs it to be flat then install the slc under the ditra.
Hi Roger,
I know these questions may seem redundant, but I’m looking specific to my DIY job so I get it right. My tile job is using 1’x2′ tiles so I feel like the floor has to be pretty flat. The sub-floor is plywood and I’m using Ditra. I am also going to be using the ATR Leveling System to attempt to eliminate any lippage.
There is just under a half inch dip in the floor across the 5 foot width of the bathroom, but when I move my 24 inch level across, there is really not much gap underneath it. The long side of the tiles will run the length of the room. Should I use a self leveler in the middle of the floor or is the slope gradual enough to just lay the tile? If I do use the self leveler, will the modified thinset still be okay over the leveler and ply? Are there any other options to addressing this? Thanks in advance!
Hi Ben,
If the gap under the level is less than about 1/8″ then you can just make that up with thinset as you set the tile. If it’s more than that you can use self-leveler over it. Yes, you can use modified over the slc.
Hello, I am tiling a basement kitchen and the concrete is 2 years old. I put a sealer on it about a year ago (foundation Armor 2000) that says you can still tile over it. After reading countless blogs and to be safe, I sanded the area with a concrete prep tool from home depot and believe the surface it ready to accept tile. After going back and forth on using Red Guard and Flex bond mortor for the tile, I decided to purchase Ditra from Home depot and Tec full set plus from the local tile company. I am concerned after spending so much on the dirtra that it may not adhear to the concrete floor. After reading several posts, I also purchased a 3/16ths v notch trowel to spread the thinset. Could you give me a idea of the consistency of the thin set on the concrete side and any pointers to ensure I get good adheasion. Also I have a expansion crack/cold joint that runs through the center of the tile area. I was just going to cut the ditra along the crack line and set a line of tile on both sides of the crack. I would then fill just that grout line with sanded color matching caulk to match the rest of the grout. Do you think that would work? Other than the expansion crack the concrete is in great condition. Any suggestions would be appreciated as I am on a buget and am concerned with the cost of the ditra and wondering if I am overkilling it. What would be your opinion of just using flex bond directly to the concrete if in good condition and no cracks other than the expansion joint? Thanks again.
Hi Roger,
We used to have peel off tiles on my kitchen, we are now in the prosses of doing porcelan tiles and useing tile membrane with tile membrane adhisive. My husband removed the peel off tile but, refused to remove the 1/8 inchess luan. Before we put down the peel off tiles of course we put an adhised on the luan for the tiles to stick better. Now he wants to put down the tile membrane over the sticky luan instead removing the luan to the sub floor. What wiil happen if he does not follow the proper procedure when using tile membrane without the tile membrance adhisive?
Hi Daisy,
Your tile installation will fail. The luan HAS to be removed. He can remove that, or he can remove the new tile in 4-6 months and replace the whole thing, at which time I’m certain he’ll remove the luan willfully.
Hi Roger,
My question to you is: can I self level with SLC over schluter ditra heating membrane? It’s an area of about one square meter and off by 5mm (sorry for the metric thinking). The membrane is tightly bound to the plywood floor by a polymer modified thiset mortar – Ardex x5. The tiles to be installed are 20’x20′. Thank you for your experience and willingness to help others.
Mihaela
Hi Mihaela,
Yes, you can use the slc over it in that area.
I will soon be laying 650 sq ft of 12″ sq travertine in my basement over concrete. The area consists of a bedroom, hallway, laundry room, a closet and a large tv room.
I have two questions: is it acceptable to lay the tile on the diagonal over ditra? Can you make any recommendations about expansion joints without knowing the dimensions and layout of the rooms?
Hi Wes,
Yes, you can lay it diagonally. You need a soft joint every 20′ – 25′ in each direction for interior installations. Installations which are exposed to direct sunlight need control joints every 8′ – 12′.
Hi Roger:
I realize now I will have to use a modified thin-set on top of my concrete overpour beneath my 1/4 inch thick Ditra. My above ground hydronically heated overpour in my 4-season sunroom is flat and generally level. I will be installing 6×6, 13×13 and 13×20 porcelain tile as the finished flooring over the Ditra. Do I have to do anything special like seal the concrete before applying the modified thin-set or is it sufficient to just wet the surface well (leaving no standing water) before troweling on the thin-set with a notched trowel to install the Ditra?
Hi Leo,
Not sure why you realize that, schluter wants unmodified over concrete, even over heated hydronics. A stance with which I vehemently disagree, I would use modified. But you WILL lose your warranty. Do not seal it! It hinders the bonding. Clean it well (sponge or mop) and leave no standing water.
I have a question. I just had a contractor install 850 sq ft of wood grain porcelain tile in my house, where Hardiebacker was simply screwed with tons of screws to the plywood subfloor everywhere including wet areas…
Do I have a problem?
Thanks
Hi Vikali,
You do if there is no thinset beneath your backerboard. If there is not then it is installed improperly.
Hi! I have two layers of vinyl on top of plywood, on top of wood subfloor. I’m told that there is likely asbestos in the glue in bottom layer of vinyl due to age of house, and I should leave it alone. I really want to lay tile over it. Ditra says that multiple layers of vinyl are unacceptable, is there something I can do to still lay tile without raising the floor height too high? Is there a work around for using ditra over two layers of vinyl? They are inseparable at this point. Thanks for any input!
Hi Sandy,
No, there is no work around. If you want tile over that you’ll need to go over it with another substrate before installing your ditra. Your best option is 1/4″ backerboard with thinset beneath it. That will give you the lowest height. You can use 1/2″ plywood, but that would give you an additional 1/4″ over your vinyl.
Hi,
I just read a blog post on another tile help/DIY blog. The guy has been laying tile for over 30 years, and he basically said this product was crap. He seemed to have some good points. He asked for comments from other tile guys. Maybe you could take a look?
Thanks.
Diana
Hi Diana,
I’ve removed your link, I don’t put links on my site that contain extremely erroneous information. I almost didn’t read past the first paragraph, where he states the ‘water barrier’ properties of hardi – it has none. Zero. But I did push on…
When he began explaining why he does not like ditra he lost me. He states that the “manufacturer requires the use of unmodified thin set mortar to both install the “Ditra” membrane on top of a wood(en) sub-floor” – they do not. In fact, they require modified thinset over a wooden substrate.
He goes on to state that “This type of thin set is the lowest quality type of thin set available costing like $5 per 50 lb bag. Right on this bag of thin set itself it says “for use on concrete floors”. First – it DOES NOT state that on the bag. Secondly he is obviously unaware that there are a LOT of different unmodified thinsets. Notice the particular unmodified he used, according to his photos, is customblend, the stuff I plainly state is only good when used as a sandbag?
Also, according to his photos, he is stating that ditra is garbage, while showing an installation of ditra-heat, it’s not the same product. His ‘reasoning’ and points he’s making seems to be a bit convoluted to me.
And using the phrase ‘common sense and SCIENCE dictate to me…’ is inaccurate, as it is obvious he is not educated in the science of how ditra works.
Now that I’ve put that up there for my regular readers, this is the part for you in particular: I have removed your link. I do not appreciate someone coming onto my blog to support or feed traffic to YOUR blog. I am not here to promote you. Or did you forget that you are one of the authors on that particular blog?
I do not appreciate someone trying to stir up shit about a product I’ve written about without being PROPERLY EDUCATED with that product. Seemingly, again, only to promote your blog. If Chris would like to have a rational conversation about ditra and how it works, the science behind it or unmodified thinsets, or anything else tile related I’ll be more than happy to do that.
But you can take your blatant self-promotion elsewhere, this blog is not here for your personal use, it is here for mine and my readers.
Nice try, though, not quite as blatant as most spammers.
Hi,
I understand. I responded to your post on our facebook page. I honestly was not trying to spam or grab people follow me to the other blog which had an opposite opinion then yours. I was trying to get clarity since Chris’s post was intended to help people; he really felt from he’s experienced that this product was not a good one, and that the instructions his customer was given were wrong. Of course we like to get all sides, and he felt there would be some installers who might disagree with his post. But he feels his facts speak for themselves, and when I needed to find an authoritative voice, I checked here since I linked an article to you once. I thought maybe seeing his perspective you may have missed something before, or you could clarify the major concerns he had. I meant no disrespect or ill intentions. It was perhaps not the best move, and I pulled the article so Chris could read the comments and review his piece. I too, needed to do more homework, so I take responsibility. Unfortunately, when I pulled the post, I lost the comments. I’ve spent hours trying to retrieve but it’s impossible. Chris insisted on putting the post back up, and I just want people to have multiple opinions and have the opportunity to make good choices. That’s what our blog has always been about and Chris invited others to comment. Again, I apologize and understand your perspective.. Thank you for you time.
Hi Diana,
I would love to believe that – I simply don’t, sorry. See, I’ve been doing this a LONG time and if there’s one thing on the internet I can recognize from a mile away it’s damage control.
You did not respond to my post on your facebook page, in fact my post on your facebook page has mysteriously vanished, as did the six or seven comments on the blog from TILE EXPERTS, the people he asked to comment, telling him the product was installed incorrectly and with incorrect materials.
Of the two of us you are the one who does SEO for a living, you know damn good and well the link you posted on this site was for that purpose. Trying to play to my ‘authoritative voice’ doesn’t fly with me, sorry. In over 23,000 comments I have on this site you have not shown up once before yesterday with the ‘hey this guy disagrees *google bait*’ ploy. I see it a LOT.
So try to look at it from my end: You show up, having never interacted with me or this site visibly, and drop a link right in the comments to someone with a dissenting opinion. I remove the link and reply, because it IS obvious to me that Chris cares about his profession – most of these go straight to the trash folder. The comments left on his blog (of which YOU are an author as well, likely run it from behind the scenes – a fact you failed to mention when dropping links) were not attacks on him at all, simply information from EXTREMELY well-informed and educated tile professionals pointing out that the premise of ditra not being a quality product seemed to hinge on the fact that the product was installed incorrectly and the improper materials were used.
Every one of those comments disappeared within 24 hours.
I went on his (yours? I’m not sure at this point – doesn’t matter) facebook page and informed him that those comments were NOT intended as a personal attack, simply that he should be educated in the materials being used before bashing them on a public website under the guise of an expert.
That comment disappears within 24 hours.
Catching a theme here? Chris has hired an SEO expert – that’s great for him. Chris does not seem to like ditra, that’s completely fine, but I feel an opinion like that should be formed after a proper installation and after learning the science (something he SPECIFICALLY invokes in that blog post) behind the product. It’s obvious that has not been done and, as with most who admonish any product, a judgement has been formed from an improper installation. It’s akin to saying all silicone is shit because I had mold behind it in my tub when I was in college.
He asked for professional opinions and he got them, and they vanished. I understand, it’s all a big mistake. My, as well as every other professional who commented, intention was to educate about a product being used a lot in order for them to be PROPERLY installed and not have failures. Failures give people the opinion that these products are garbage – an opinion that Chris has obviously already formed, specifically because of an improper installation. We do that in an attempt to raise our profession as a whole – not to tear down or attack any one professional.
Personally I have problems with people attempting to promote a product (in this case a blog or business) when they know little about the technicalities of that product or business. That was the reason for my facebook comment, letting him know that there is someone representing his business without proper training or knowledge of what they are promoting. While there is absolutely a place for what you do, coming onto my blog and posting ‘hey this guy disagrees with you’ as a method to drive traffic to it (and you know damn good and well that’s what it was, I know what your job entails as well) without knowing you were linking to an improper installation was a bad move for Chris. I wouldn’t want it, I have no idea what his opinion is about it.
Pulling the article to ‘review comments’ is not necessary, someone in your profession knows that. And while losing comments does happen, especially on third-party blogging platforms, the fact that my facebook comment vanished as well leave me a bit leery of believing that as well. So while I appreciate the apology I have trouble buying the sincerity of it. I wish Chris the best and really hope he realizes that all the newer products have a LOT of science behind them and require specific installation techniques, like modified thinset over plywood. One little mistake like that will cause an installation to fail, as well as giving someone the opinion that the product is garbage.
One of the main issues, and as an seo expert you should know this, is that people will google Schluter ditra. They will do this after I give them a proposal, or any one of a thousand professionals give them a proposal, and Chris’ post will come up with a ‘reality check’ about a product he does not understand. It makes me, and thousands of others, look like WE don’t know what we’re doing, when in actuality it’s Chris who does not know about that product. WE lose money, people highly educated in this profession are looked upon as ‘iffy’ and the profession as a whole eventually gets a bad reputation because ‘we’ use products that ‘don’t make sense from a common sense and scientific’ point of view. Get it? He’s forming an opinion based on erroneous information and I lose a $10,000 bathroom remodel.
But you got him to the top of google, didn’t you?
I have no problem with your profession, provided people doing it are educated in the profession they are attempting to promote. In this instance that is not the case, and I’m calling bullshit on it. It’s one reason I started this blog, there is a LOT of misinformation out there, yours is simply the latest. So in the same manner I apologized to Chris yesterday for him taking the brunt of this in the facebook comment which vanished, I’m apologizing to you for getting the brunt of all of this from my end. I understand you have a job to do, and I’m pretty sure no one has told you that the manner in which some people do it is damaging to MY profession. I do not like that, and I will call it out when I see it. So I honestly hope you are sincere about understanding my perspective and the realization of the mistake. And I honestly hope Chris will become educated with products he uses.
Can I install ditra over hardie backer board? If so, what type of mortar should I use to install the ditra?
Hi David,
Yes, but soak it down first and move quickly. The durarock will suck moisture out of your thinset fairly quickly, so you want to make sure you are laying the ditra into fresh thinset. Schluter required unmodified thinset when installing over cement board.
Quick question can you lay Ditra over cement board?(durarock)
Hi James,
Yes, but soak it down first and move quickly. The durarock will suck moisture out of your thinset fairly quickly, so you want to make sure you are laying the ditra into fresh thinset.
I leveled my plywood floor with ultimate self leveling floor compound from 1/8 to 1/2 inch thick. What thinset do I use to attach ditra to the ultimate self leveling compound and what thinset from the ditra to the tile.
Its a kitchen 13×20. The self leveling compound has hair line crack all through it. Will that be a problem.
Hi Terry,
The hairline crack is a shrinkage crack, it won’t be a problem. Schluter wants unmodified thinset both under and over the ditra in that situation.
Hi Leszek,
Yes, you can use all-set for both.
Ditra-mare. I’ve consulted your site on several occasions and do very much appreciate all the excellent free advice. However, on this occasion I need a little extra help before I create a serious mess. After using two bags of SLC on an unlevel floor in our mudroom 9×10, I just installed Ditra (first time for me) and it seems I’ve got bumps everywhere. I just did a trial setting up the tile and it is a mess. Lots of small bumps. 1/16 to 1/8th I’d say. What would you advise as the least messy cleanup of this disaster? SLC over the whole thing? 1/4 hardi over the ditra? I just have no idea. Out of my element on this one.
Thanks,
Rian
Hi Rian,
Any idea what has cause the bumps? I would think the easiest would be removing the existing ditra and scraping the slc to a flat plane. Without knowing why you have the bumps it’s difficult to say with certainty that slc would work out. While it would likely be the easiest solution, you may be pouring it over a substrate which is not properly bonded, which may lead to hollow areas beneath your slc. That’s gonna cause problems down the road.
Removing the ditra will likely leave a good portion of the fleece backing, but that can be scraped up, and you can always go over the whole thing with slc once the ditra is removed. You can install tile directly over the slc if you’re concerned with height issues.
Thanks for your thoughts. Well, the bumps are from using too much/uneven quickset under the ditra. It’s down good alright, but way too many bumps – I hurried it in a panic and that is the DIY result. (lesson learned). I’m probably go with your latter suggestion and just tear it up, scrape it down and do it right. Thanks again. -Rian
I purchased ditra for a small bathroom, 10×5. It has a plywood floor, which I added screws every 6 to 8 inches to take out the squeaks. Should I install another layer of plywood or can I go right to the thinset/ditra? In the past I would add cement board and screw it down every 6 inches. This is my first time using the ditra product. Also, another question, the room along the 10 foot measurement, runs high to low, a consistent grade gap of 3/8 from back to front. Would I just try to level by starting with a light coat of thinset at one end, and build up to make up the 3/8 at the other end? Is it better to do that on top the ditra before the tile or prior to placing the ditra mat down? Please advise.
Hi Mike,
You can go right to the plywood with the ditra. If the floor is a flat plane you don’t really need to level it. If you want to it’s better to do it with the thinset beneath the ditra.
I have an embarrassing question…. i’ve tiled before but this is my first floor. It’s a powder room, 8’x3′, on a wood sub floor. I’ve removed the linoleum, but there is a little paper/glue still remaining on the 5/8′ plywood. The linoleum was glued evenly under the whole floor (not just the perimeter). I have a heat gun and a floor scraper, but I don’t want to accidentally “eat into” the plywood. I don’t own the tools to cut plywood, so I was hoping to clean up the plywood. I’ve had read that the old glue absolutely has to be removed as it can ruin future flooring installations. After all that, here’s my stupid question: can you confirm that I must remove all old glue before using Schluter?? Thanks!
Hi Victoria,
Unfortunately yes, you must remove it. Try laying a really wet towel over those spots overnight, then it should just scrape right up fairly easily the next morning. Most of that glue is water-soluble.
We are planning on converting a living area with old hardwood flooring into a bedroom and bath, and want to tile the bathroom. We also want to use radiant heat under the tile. Can Ditra be placed on top of the hardwood flooring and radiant heat mat, or should we consider another base for the tile?
Hi Joe,
It can not go over the hardwood. You need to either remove the hardwood or go over the hardwood with plywood or backer first.
Hello. We purchased a home from the 1980’s and it has k-3 particle boards covered by linoleum in the bathrooms as well as the kitchen. In that situation, are you able to put Ditra over top of the linoleum (some sites say that is ok), or must it be ripped up and a new subfloor installed?
Hi Mom (mom…is that you?
),
ALL particle board needs to be removed and a proper plywood substrate needs to be installed. Sorry, I know that’s not what you wanted to read. Put those kids to work!
We just installed Ditra over plywood in the kitchen and have tiled half of that area as of today. We also installed Ditra in the bathroom over a combination of existing tile and plywood that we leveled with floor stone but have not installed tile in there yet. For both areas, we used UNmodified mortar to set the Ditra in. I read the manual again because of some conflicting advice we received from two different stores, and I am really concerned that the mortar was not the right kind in at least the kitchen, if not both areas. Please tell me we don’t have to pull it up…. or that we can salvage it somehow. What are the consequences of leaving it down? Modified is suggested for plywood, but is it absolutely required? It says nothing about existing tile as the substrate. Thanks!
Hi Leah,
According to schluter yes, modified is required over plywood. In reality you should be fine provided you have a sturdy enough floor and the proper deflection ratio. Over tile you should have used a modified thinset approved for use of tile over tile. IF you scarified the surface of the existing tile you should be just fine there as well. I have no idea what ‘leveled with floor stone’ means?
I am about to lay Ditra heat in a bathroom 5 x 6 that has a small hump in the center of the room approx 1/4 inch. what is your suggestion for how to level this and is leveling needed. it has a 3/4 plywood subfloor and I’m going to lay 13 x 13 tile.
Hi Joshua,
Yes, it needs to be flattened. You can either sand down that area, use self-leveling cement, or use a larger trowel on the rest of the area when you install backerboard. If you do the latter comb out your thinset, leaving it nearly non-existent over that area, lay the backer into it and flatten with a straight-edge, let the thinset cure, then screw it down. You can do the same with ditra (no screws
).
Thanks for sharing your vast knowledge with the DIY’ers. I have installed ditra heat as my substrate and put my heating wire in. Do you recommend filling the waffles with thin set, “in every direction”, one day then laying tile or doing both steps at once? Your tiling guides are worth every penny. Thanks again.
Hi Brent,
Whichever works best for your timeline it fine. If you aren’t going to be able to install all the tile in one day I would fill the waffles first, then you can walk and work over it without worrying about damaging anything.
Tile on a covered porch: my installer doesn’t want to use schluter saying that tiles are more likely to break vs backer board. Is this true?
Hi Ed,
It depends on your freeze/thaw conditions. Water can get into the cavities of the ditra and, if it freezes, may compromise the bond. So he is correct depending on your climate. Backer would work better in that situation.
I have a small hall bath, approx 5’x8′, just torn down to the subfloor after uncovering a water leak. Subfloor is 3/4 plywood, and still in good shape. What is benefit to using Ditra vs. Hardiboard as underlayment for 12×24 porcelain tiles in this setting? Thanks for being super cool!
Hey Dave,
Ditra is less height, gives a better separation between structure movement and the tile, allows vapor dissipation under the channels below the membrane (more for installation over concrete than wood). There are other minor ones, but those are the main points.
What are your thoughts on mosaic penny tile with Ditra? I am doing a tiny bathroom reno myself and although I told them what I was using, the tile store guys didn’t mention the size of my tile being a bad choice for Ditra. I hate to return it but I don’t want to replace this floor in a year… Thank you so much for such an amazing site!
Hi Adriane,
I would not use penny rounds on ditra, it could definitely cause a problem. Schluter doesn’t want anything under 2″ square over it. I would change to a backerboard or change your tile.
And I know that isn’t what you wanted to hear. Sorry.
I am the owner of an old house with 2 layers of 5/8 OSB and a layer of 1/2 cement board. The cement board has been painted over (that is another story) i can rough it up some with a sander if necessary. What type of thin-set should I use from that to the ditra? Any advice would be welcomed.
Hey Lance,
You can rough it up with a belt sander and use a good modified thinset to install the ditra to it.