ProvaFlex vs Ditra

by Roger

Ditra vs ProvaFlex

Ditra vs ProvaFlex

That’s right, I said typed it! Bring it on :guedo:

In the last month or so there has been a lot of hype about Loxscreen’s new polypropylene tile underlayment membrane. That’s just a big phrase for plastic tile underlayment. It is being marketed as a replacement product for Schluter Ditra.

Since I use Schluter Ditra almost exclusively as my preferred underlayment for floor tile I felt it would be a good idea to give this stuff a try. I did not do this in order to find a replacement for Ditra, I’m extremely happy with Ditra. I do feel, however, that due to the way this product is being ‘marketed’ to consumers and since it claims to be a replacement for a product I regularly use, people may want a professional opinion about the way it performs. AND! if there is something better out there – I want it.

There is also another very good reason I decided to do this: there happens to be one person all over the internet claiming this product to be better than a silk jockstrap. I’ll save that rant for the end of this post but suffice it to say that, at the very least, I vehemently disagree with his marketing tactics. If you would prefer to start with that rant please feel free to scroll to the end.

I will attempt to be as unbiased as I can as a firm believer in Ditra and the mechanical way in which it works. So to understand the key points of this comparison we should first begin with a basic understanding of that. I will just give an overview of a couple of key parts but you can read the official line from Schluter Here.

Tile being installed over Ditra

Tile being installed over Ditra

Schluter Ditra is a polyethylene membrane with square dovetailed cavities and an anchoring fleece laminated to the underside. The Ditra is attached to your flooring substrate by embedding the anchoring fleece in thinset (modified or unmodified depending on the substrate to which you are installing it). The dovetailed cavities on top are then filled with unmodified thinset and thinset is combed over the top and your tile is installed to it. The photo to the right shows the tile being installed.

The key component  is the dovetailed cavity of the Ditra. See, the thinset does not actually adhere to the polyethylene (which, for purposes of not confusing anyone, and you know, not sounding like an uppity bastard, I will hereafter refer to as the ‘orange plastic’) This is completely normal and in no way compromises the installation – it is normal and on purpose.

Ditra utilizes a mechanical fastening rather than a chemical one. Thinset ‘sticking’ to the orange plastic would be a chemical bond to the plastic. Filling the dovetailed ‘waffles’ forms a mechanical bond by locking the thinset into the cavity.

Cross-section view of Ditra's dovetailed cavities

Cross-section view of Ditra’s dovetailed cavities

The photo to the right is a cross-section view of Ditra. You can see how the cavities are angled back from the top opening of the cavity. The cavity gets wider as it gets deeper – that is the ‘dovetail’. After this is filled with thinset and the thinset cures it is nearly impossible to pull the thinset out of this cavity – it will not move, it’s locked in there. That is what I mean when I refer to a ‘mechanical’ bond.

A mechanical bond is the main reason I use Ditra. This will allow the ‘micro-movements’ in the substructure without transferring them through to the tile installation. The entire tile installation becomes one large monolithic structure which is able to move independently of the substrate. This means that the joists below your floor, or the concrete, can expand, contract and shift with the small movements inherent to structures without compromising the tile installation.

Or, more specifically and simply, when winter hits and your joists expand a little bit your tile and grout will not crack.  Get it? Now I’m not talking typing about a major movement like a bulldozer crashing into the side of your house because  I someone was doing roadwork while intoxicated. I mean the normal movements of any structure under seasonal changes.

That is basically how and why Ditra works. ProvaFlex, according to all the marketing and hype, is supposed to do the same thing. In fact if you read through all their (online) literature (yes, I have) it is nearly identical to everything Schluter has published about Ditra. So let’s start with the similarities.

Both products are marketed as an uncoupling membrane (this is what I’ve described above – the independent movements).

Both are marketed as having waterproofing ability when coupled with the respective band or tape for the seams. However, ProvaFlex is not recommended for use outside of a covered structure – you’re not supposed to use it on your porch.

Bottom of ProvaFlex next to bottom of Ditra

Bottom of ProvaFlex next to bottom of Ditra

Both are marketed as having vapor management properties. This is a method of equalizing or dissipating vapor through the open channels beneath the membrane to prevent moisture build-up below your substrate. Confused? Nevermind, then, for the sake of argument let’s just assume that they both do that.

Both have an anchoring fleece laminated to the underside. The anchoring fleece is what is set into the mortar on the substrate to attach the membrane. They appear identical to me, and are identically difficult to pull off of the plastic membrane itself. I didn’t put a scale on it to gauge the difficulty, but it seems nearly identical to me – so let’s go with that. They’re the same.

Both are a form of plastic. Ditra is polyethylene and ProvaFlex is, well, I’m not really sure what ProvaFlex is. The online literature states it is polyethylene as well but the written literature included with the product states “Polypropylene material – Impermeable against other building chemicals. Easier to install and lays out flatter than polyethylene.” I do know that it did indeed seem to lay out a bit flatter than Ditra but that may be due to the smaller cavities in the top or the type of material – I can’t say which for certain. Someone apparently has their wires crossed somewhere and it is my opinion that it is the available information online because, well, why in the hell would you send erroneous information with the actual product? But, I really don’t know. There will be more about this in my rant. :D

So it would seem that both products are marketed with identical benefits. But we all know that without actual hands-on use I could market a baseball bat as an environmentally friendly hammer – doesn’t make it true. So let’s move on to the differences.

Top of ProvaFlex

Top of ProvaFlex

The ProvaFlex has an overlaying mesh or webbing attached to the top of it. I like this. It just seems like it would add more of a mechanical fastening to the membrane and stiffen up the installation itself. Whether that is actually true or not – I have no idea, but I still like the fact that it is there.

ProvaFlex with overlaying mesh removed

ProvaFlex with overlaying mesh removed

When I peeled this webbing off, however, I was a bit disappointed in how easily it was peeled back. I expected it to be nearly as difficult to remove as the fleece on the underside – it was not. It is attached fairly well but not nearly as well as I would have liked or been comfortable with. Maybe I’m just an anal bastard a demanding consumer – I don’t know. I still like it, though.

Ditra’s surface is comprised of 3/4″ square ‘waffles’. ProvaFlex’s surface is comprised of alternating 3/4″ circles and 7/8″ ‘flared’ squares – or whatever the hell you wanna call that shape, with raised circles in the center. Shape-wise (is that even a word?) I don’t think it makes much of a difference but I can’t say for sure one has the advantage over the other so I’m callin’ that a wash. I will say type that the ‘pillars’ created by the Ditra will have a bigger, more consistent footprint in contact with the substrate.

The thickness of both products seem identical but if you slam a micrometer on them I would guess the Ditra is just a platypus hair thicker. (A platypus hair is really thin, by the way. Don’t ask me how I know that, let’s just say it involved a midget and a case of scotch…or so I’ve heard  :whistle: )

So this far I would call it fairly even as far as a practical application indoors. If you don’t agree, well, start your own damn blog. I’m callin’ it even – up to this point. There is one major difference that is almost certainly a deal-breaker for me – the ProvaFlex cavities are not dovetailed.

The online literature and marketing hype – all of which compares it as an alternative for Ditra at a lower price – states, and my computer quotes “…with a grid structure of square, cut-back cavities…” Just a bit (ridiculously) misleading if you ask me. The shape of the cavities is most certainly not square and if by ‘cut-back’ they mean dovetailed – they most certainly are not that either.

This may or may not be a marketing ploy – it is not for me to say (yet) but the description can ‘technically’ be described as accurate if by ‘cut-back’ they mean the shape of the funny looking squares and by ‘square’ they mean the shape of the cavities in the z-axis, as it gets deeper.

Physical literature included with ProvaFlex

Physical literature included with ProvaFlex

This, however, only seems to be on the online marketing sites. The physical literature included with the product itself specifically states “Square Cut Adhesive Cavity” pointing to a square (not dovetailed) cavity on the surface of the membrane. It does not seem to me that the Loxscreen company, the manufacturer of ProvaFlex, is attempting to pull the wool over anyone’s eyes as far as comparing it as an identical product in form and function. Not as far as the mechanical bonding process, anyway. It appears to only be the online marketing.

Cross-section views of ProvaFlex and Ditra

Cross-section views of ProvaFlex and Ditra

The photo to the right shows the cross-view of both products right next to one another. If you click on it and ignore my shitty photography skills you can plainly see the dovetails in the Ditra (top) and the square (or slightly rounded) cavities in the ProvaFlex (bottom).

If you can envision filling the cavities of each product with thinset and allowing it to cure then pulling straight up on each, what’s gonna happen? Without the mesh or webbing on the ProvaFlex that little fill of thinset will pull straight up and out – the Ditra will not, it is locked in due to the dovetail.

I’m no expert or anything (yes I am) but it appears to me that the ProvaFlex’s mechanical bond relies on the mesh or webbing attached to the top of the membrane. The method of the mechanical bond is different.

The bond for the Ditra relies entirely on a mechanical process, the aforementioned dovetails. The bond for the ProvaFlex relies also on a mechanical process, the webbing or mesh attached to the top of the membrane. This webbing, in turn, is attached by means of a chemical process.

I’m unsure what this chemical process actually is. I’m certain it is a trade secret and they would send black helicopters after me if I were to divulge it. I don’t know – I don’t care. It does not change the fact that the bond with ProvaFlex is not truly and entirely mechanical. The entire bond of your tile installation relies on the process and durability of the mesh webbing attached to the face of the ProvaFlex membrane.

So when you decide which product you want to use under your tile installation you should take into account the method of attachment. ProvaFlex seems like a decent product for a small application such as a small bathroom without excessive traffic or maybe a small countertop. It is entirely up to you whether to use it or not.

It will work to an extent and with certain applications. I just did two bathroom floors with it which I now own. That means if this stuff fails I’m paying to replace them, so it better not fail. But with any new product someone has to take that risk. If it does fail I will absolutely let everyone know – believe that.

This product will not be a replacement for Ditra for me. Anywhere I can use ProvaFlex I can use Ditra instead. I don’t believe the reverse to be true. If you install hundreds or thousands of dollars worth of tile do not nickel and dime the price of your underlayment. Saving one or two hundred dollars now may lead to replacing the thousands of dollars worth of everything later on down the road.

I am not saying it will fail – I’m saying I don’t know. With Ditra I know.


This is not a rant against ProvaFlex, it is a rant against particular individuals marketing ProvaFlex on the internet. If you want to know who it is – google it, this jackass is all over the place.

I have no problem with marketing a product. I do have a problem with the method it is gone about. If someone needs to bash another company in order to sell their own (or one they are shilling) it is not only disingenuous, it is absolute bullshit.

The marketing descriptions and literature available online from this particular individual seems to be at complete odds with the product’s own marketing information. That is a big red flag.

This person apparently has had a disagreement or falling out with the Schluter company (as well as a couple of other very large, major companies in the industry) and has taken it upon himself to attempt to discredit everything about them.

Under the guise of ‘Schluter is crap and they screwed me so here’s a better product…’ he attempts to peddle ‘Prova’ products claiming they are better engineered and cheaper than Schluter products. They are cheaper, no question. Better engineered? You be the judge, that’s why I did this.

This guy bashes everything about Schluter, attempts to make false arguments such as ‘thinset doesn’t even adhere to Ditra’ (no shit) then turns right around and copies their marketing literature and substitutes his product in place of Ditra and Kerdi. THIS is where the inconsistency in things such as the polyethylene and polystyrene differences come from. Oops, forgot to change that part – jackass. The “…with a grid structure of square, cut-back cavities…” quote earlier happens to be exactly how Schluter describes Ditra – which is accurate.

The descriptions, methods, and even chemical makeup of the product, is at complete odds with the product’s own literature. Why would that be? I have absolutely nothing against Loxscreen or Prova-flex, hell, I tried it myself. I do take issue with assholes attempting to discredit one product in order to sell another. I believe if Loxscreen wishes to own a decent market share of this industry in the United States they should prevent this asshole from selling their products.

ProvaFlex may indeed be a product inspired by Ditra but it works differently, people need to know that. Attempting to force-feed the idea that it is an identical but cheaper product is bullshit. You are taking advantage of people inexperienced and uneducated about what the product should do for the purpose of profit. Please kindly go throw your own dishonest ass off a large cliff.

Please, please research anything you plan on using for a tile installation. Get more than one opinion – always. Even if that one opinion is mine (which is right, by the way) go get it from someone else. The better educated you are about it the better off you will be.

Now that you know how ProvaFlex works you can make a more informed decision about whether the amount you save is worth it for your particular application. If you want to use it and it sounds like the right product – use it. Just don’t buy it from the asshole.

If you have any questions please feel free to leave a comment. I’ll help if I can. Please understand I’ve only used this product for one installation so all my information is based on that. I have used Ditra (literally) hundreds of times. If you are the particular asshole I’m ranting about – and you know who you are – stop taking advantage of people’s inexperience and feel free to go find the aforementioned cliff.

Rant over. :censored:

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Chris Schmidt

3/4 Plywood ? does not mean very much . If the framing underneath is not done properly and we find this all the time in repairsituations that the framing is way to far apart, then any floor will start to swing and bend. Anything you put on top will not hold in the longrun. Gravity is a Beast plus movement
To check this is a challenge on its own. Only easy if the floor is already damaged,then the Homeowner agrees mostly to the proper repair.
Before this good luck.



Excellent article, thank you.
I have a tile shower stall. The floor was built twelve years ago on a mortar bed with a membrane. The membrane had to be cut and patched due to the shape of the stall. Now, when the drain is temporarily blocked to test the membrane, water leaks out under the floor. The tile is not loose. Could one Ditra over the existing floor tile (1″ squares) and 6″ up the wall, refit the drain to the Ditra and then tile over the top rather than removing the stable mortar bed?
Thanks Again


Terence Murphy

My basement floor is concrete and covered with glued down vinyl 1×1 floor tile. I want to replace with a natural stone or tile floor
What’s the best way to proceed



Hi Terence,

The vinyl will have to be removed as well as any paper backing from the vinyl or glue left on the concrete. Scraping it up really is the easiest way – and it isn’t very easy.


Robert Desbruslais

Hi Roger I have just carried out a survey on a huge house with this system under the tiles. Pot and beam floor. House is 5 years old and several tiles are flexing and squeaking a little. Any ideas?



Hi Robert,

I would need much more information to ponder an educated guess as to the reason. Do you know the deflection rating of the floor? Type of substrate beneath the prova? Brand and type of thinset?


Robert Desbruslais

Hi Roger. All I know is its a pot and beam floor. It’s a high end building, very high spec, indoor pool etc and good quality workmanship and materials. Vendors are not technical and have little info.



Well, my first guess would be inadequate coverage of thinset beneath the tile, but you would need to remove a tile to verify this. I would bet that when you remove one from the field (make sure it’s a full tile in the middle somewhere, not a cut tile) that there is little or no thinset on the back, and you may even still see trowel lines ghosted on the back of the tile. This happens for several reasons, number one being not backbuttering the tile, along with spreading too much thinset at a time, not a large enough trowel, and improperly embedding the tile into the thinset. The reason you want to check a full tile is because much of the time on commercial work one crew will come in and do all the full tiles, then the next day either them or a different crew will come in and do the cut tiles, oftentimes applying the thinset to the tiles themselves rather than the substrate. That’s where I would start.


Robert Desbruslais

Excellent I will recommend that further investigation thanks.


David Keeney

I have been told by several contractors and a a Ditra rep you can coat Ditra 100% and then come back the next day and trowel modified thin set over the Ditra with porcelain tile. What is your opinion and will that cover Ditra Warranty. Thank You David Keeney



Hi David,

I have absolutely no problem with that method at all. As far as the warranty – I would get that in writing from whichever rep told you that. I don’t believe that you will retain your warranty with that method.



Hello Roger! I have your shower books and trust your opinion. I have a new project and I was hoping to get your opinion.

I am confused about how to proceed with preparation of my floor for tile.
About 150 sf floor to cover in upstairs bathroom with separate toilet area. Construction is ¾ T&G OSB (unknown Exposure Rating) over wood I Beams (I Beams are 12 inches wide (deep?) and seem to be spaced 19.2 inches apart). Longest span within the room is 11 feet – it may run out to 15 feet before there is a wall (support) below. – I know they used adhesive on top of I Beams).

New tile is wood look porcelain 6 x 36.

We had a leak (small drip – while gone for a week) and floor got wet. The OSB subfloor is a bit uneven now (and may have been since new). It was mostly covered with carpet except the toilet area and a “landing” area for the tub/shower. – Both of these areas were tile over ½ inch Durock. The Durock was nailed directly on the OSB (no thinset). These two small area have held fine for 16 years (age of house) – but it still seems that installation was incorrect.

I want to do the floor prep correct as reasonably possible.

It seems a given that the cement board (all types) have to be bonded to the sub floor. This is 1st area of confusion. I have read (somewhere) not to put thinset on top of OSB – Drock website states to use latex modified thinset or Type I Organic Adhesive. And notes the OSB should be Exposure Rating 1 or better).

I guess some will say go ahead and thinset cement board to the OSB. If that is the case any thought to covering subfloor with tar paper or rosen paper? – I do not know the OSB exposure rating…

I was thinking I would cover subfloor with Luan. I like the idea that (a long time) down the road you could remove the floor “cleanly” after the Luan is removed – back to the original subfloor. But now I have read to never use Luan between OSB and cement board… – Is that true?

I have also seen some 5mm “underlayment board” in the store – is that a consideration for this application?

Next thought is to use ¼ plywood screwed to the OSB and then thinset/screw ¼ cement board- I would think that would be a very good foundation for the tile. Of note here is that I would rather not have the height build up but I am willing to make that trade-off for a trouble free install.

I got an opinion to use 1/2″ BC plywood (a min of 3/8- 1/2 is better) over the OSB. ( I seem to be on the questionable side of if my structure is stout enough). Now because build up height is becoming a concern it was suggested to use Ditra or StrataMat or even green skin on top of plywood – to save height over 1/4 backerboard.

Are one of these ideas a solid path forward? – or please suggest a good sequence for worry free install.

Thanks in advance for your valuable knowledge and experience. I am OK spending a bit of extra time/money to “do the job right”. I really want to eliminate any possible future problems…



Hi Matt,

First of all – everything you’re worried about stems from a misunderstanding. Durock (or any backer board) DOES NOT need to be bonded to the subfloor. Thinset beneath backer is there ONLY to support the entire sheet and fill any voids. It does not need to bond to anything – it’s a filler.

If durock’s website says to use type 1 organic adhesive – they’re full of shit. About the luan: NEVER, ever install anything with the intent of it being ‘easy’ to remove in the future. Anything I put down I do with the intention of the person ripping it out hating me for eternity.


Prakash Mohan Choudhary

in kolkata, West Bengal, India how we can get the material



Hello Prakash,

You should contact the main company’s helpline number, they can tell you where to locate it. Schluter’s number (for US) is 1-888-472-4588


Thomas Linehan

Most excellent post, I’ll buy you a beer or 3. I’m trying to find a waterproofing membrane for a large houseboat,75′ 55’x24′ interior, steel frame with 2xflat joist@ 1′ o.c. with 3/4″ adventeck ply, any thoughts?? Thinking flexible??? Thanks



Hi Thomas,

Your best bet for walls would be a liquid waterproofing membrane. They are also a crack suppression membrane, which means they have a bit of give to them if needed. Hydroban would be perfect for that scenario for the vertical walls, and ditra would be ideal for your floors as it won’t transfer substrate movement through to the surface layer.



Userper bastards rant. Check it out. From my experience with ditra I have to say that its proof is in the pudding. It just works. My only quarrel is the price. They sure are proud of that sh_t! I haven’t really seen or heard of any other effective fastening systems for tile installation. Well maybe the old mortar bed & mesh. But things have come a long way from that, which I had the pleasure(enormous PITA) of doing once. If you really don’t want your tile to move, screw it to the floor (I’m bullsh___ng). A customer actually suggested that once. I had no rebuttal. I guess it’s nice to see that someone is offering an alternative to ditra. Is it inferior, who knows? But there is a damn good reason why ditra is what everyone uses. It just works.


Double D

Would you use Ditra on top of 3/4 plywood for tiling? Or would you say that one layer of 3/4 is not enough to adequately support the tile?

Room is 8′ x 11′




Hi Double D,

It depends on what particular type of tile I was installing. Porcelain – possibly. Stone, no. It also depends on the deflection rating of your floor, the spacing of your joists, the unsupported span, etc. There is much more to it than simply an 8×11 size. :D



How can i glue Ditra to the linoleum? Can i buy that kind of “glue” at home depot?


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