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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We are less concerned about cracks than we are about moisture coming from below the concrete base of a below grade slab built in 1920. What is your recommendation for us as we desire to block moisture rising from below? Lenolium squares and vinyl flooring have not stood the test of time in the past so we now are pursuing porcelain tile. Another factor is the extreme temperature change from winter (sub zero) to summer (80 degrees inside) and next to lake – so condensation is occurring and contributing to mildew indoors. The concrete has no existing vapor barrier so hydrostatic pressure is a real concern here. Based on this description do you still recommend ditra?




Absolutely! The bottom of ditra has vapor dissipation channels, it dissipates moisture and condensation below the tile.



My 1960’s molded “mastic” shower stall floor pan has cracked I need to replace it. While I’m at it I want to redo the entire shower stall. i’m assuming that my sill and part of the framing (no of it load bearing) will have to be replaced. I have a concrete slab floor with radiant heatin in the slab. I haven’t seen you mention preformed, fibreglass, tileable pans for shower stalls nor preformed, tilable, fibreglass niches. You seem to do all your work the “old fashioned” way – not that there is anything wrong with that it just seems to me that insead of building a niech or pan from scratch using a fibreglass pan and niche forms would save a lot of work. Provided of course that they fit you criteria. Your thoughts?



Hi Suds,

They work very well. However, the preformed pans rarely fit the bathrooms that I build (large, different shapes, etc.) and I am EXTREMELY anal about my niches lining up perfectly with grout lines and being specific sizes for whatever tile I’m installing, makes it nearly impossible to use the premade niches.



Two questions:
#1. I am planning to tile an existing tub/shower wall. After removing the ugly vinyl covering, it is down to very solid luan over wide board wall (very old house). We plan to put up cement board and then the tile. Can we put cement board on top of luan or should we take down to the old wall first?
#2. Do I need to use the Ditra for this application, or can I just mortar the cement board and apply tiles? These will be 8″ x 12″ tiles with a border of glass mosaic. (One issue is the thickness added by using Ditra which might answer the question about removing the luan.) Thank you.



Hi TL,

1. The luan really needs to be removed before the cement board is installed.

2. Ditra does not go on the wall, ditra is for floors. The tile can be installed directly onto the cement board.



So I broke down and purchased your Keri Shower ebook bundle — well worth the $40! Already had the Kerdi ebooks from some other site (which are fine but more is good). The Design book opened my eyes as to just how BAD my past attempts at tile have been. :-) And the Tile Tips… priceless for a guy like me, thanks!

OK, here’s my question.

Along with a new tile floor in the kitchen/living room, I’m also in the midst of a bathroom remodel which will have a walk-in shower. Decided to go with Keri for the shower (top, sides and floor) but have yet to lay the pan and only have partial Durock on the walls at the moment. And there in lies my question — I understand that Durock needs to be be supported on the edges and from what I’ve seen most recommend adding blocking between the studs to support it. I’ve also seen blocking used to support the deck mud above the bottom plate. Since I’m using Keri, would it be possible to run the Durock to the floor and then install the pan using the Durock as the wall support for the deck mud? I know that’s unacceptable with a traditional shower and I wouldn’t normally entertain such a thought but I got pipe and space issues that are making things difficult. Any thoughts?



That is exactly how I do it. When using a topical membrane you can place your substrate all the way to the floor against the footer to support your deck mud. Works like a dream.



Very nice article/blog. I found while searching for truth concerning whether or not Dural once manufactured Ditra. So far I find no evidence, only an inferior product. I too am a proud consumer of trusted Schluter goods. Got to try a free roll of Lati Crete, Strata Mat… has those similar alternative shapes. In my professional experience, the straight waffle design of Ditra make measuring and cutting a breeze, no marking instrument necessary! You either cut half ways between waffles or middle of dividing cutback ridge. Schluter Mc Dooder here! :rockon:


Paul Jahn

Roger used your site and your advice to do a still water proof shower 1-1/2 years and counting with no issues.
On to the kitchen. The old floor is five layers of Linoleum and whatever impervious glue they laid it with in the 50s 60s and 70s. If I can strip this crap off would Ditra be okay given the plywood has been coated with “lino-goo”; or should I tear it down to the floor joists and use new plywood underlayment?



Hi Paul,

Ideally new plywood. You can also get it down to the bottom layer and put an additional layer of ply or 1/4″ backer over it.


Pat Mac

Roger – great site, thanks for all your input and sharing your experiences (and your good “bad” humor rocks)!! :rockon:

I’ll will be tiling about 450 s.f. of hallways, bathrooms, mudroom and kitchen areas. Basically I’m removing all the vinyl areas, along with the 5/8″ subfloor and replacing with porcelain tile. The existing floor construction is 3/4″ T & G OSB over 2 x 10 joists at 16″ o.c. There is 5/8″ particle board through out the entire house where there is carpet and padding remaining.

* Is Ditra available in various thicknesses (so I can match up the top of tile with the carpet height)?

* Can the Ditra be installed directly over the 3/4″ OSB (the floor seems plenty stiff).

Maybe I’m over analyzing this thickness issue…my tile thickness is 5/16″, what will the total thickness be with two layers of thinset, a 5/16″ tile and the 1/8″ thick Ditra?

Thanks for help.



Hi Pat,

Ditra is available in regular 1/8″ as well as ditraXL which is about 1/4″. Yes, it can go over the osb.



I’m a newby (not totally but close enough) and I have the same question as Pat… which you kinda failed to answer. :-)

What’s the final thickness of the mortar/Ditra/mortar/Tile stack? How much can that stack be fudged to meet up with existing flooring?

I have an existing engineered wood floor that I’m mating up to that’s .7740 in. thick (Just measured it with my trusty digital micrometer :-) ). My tile is 5/16 in. and it would seem that the 5/16 Ditra XL might be in order but that only leaves 1/8 in. for both mortar layers… is that as it should be? Do I need to go with the 1/8 in. Ditra?

Somehow this seems like the wrong article to be asking these questions — you can blame Pat for that, not me. :-)

Great article, by the way. And thanks in advance for the answer.



Hi S,

I didn’t specifically answer that because it varies – A LOT. It depends on what trowel sizes you use, which depend on how uniform your tile is. If you have a 1/2 x 1/2 trowel your mortar will be 1/4″ thick, if you use a 1/4 x 1/4 trowel your mortar will be 1/8″ thick. The minimum mortar bed thickness beneath a tile when installed needs to be 3/32, that is for each layer. It is impossible for me to answer that question accurately, it could be anwhere from 1 1/8″ (with XL) up to, and beyond, 1 3/4″. It’s something that each person needs to figure out with their tile and trowels.

Ditra XL will be approximately 7/16″ with mortar
Regular ditra will be approximately 5/16″ with mortar

That’s the best I can do. :D



That’s a GREAT answer and exatcly the info I was needing! Thank you!

I have another question but this is not the article to ask it on… so now I’m off to find a better spot. :-) Is there a generic ‘ask your questions here’ link that I’m missing?



Anywhere on the site works just fine, I get them all in the same place in the back room.


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