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.

RANT-RANT-RANT-RANT!

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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Paul

Hi Roger,

Thanks again for all this information…very helpful.

I’m going to use Ditra when we tile our bathroom floor. We ripped up the old tile and took some shallow chunks of the plywood floor with it. The floor is flat and the shallow spots are no deeper than 1/8″. Do i need to level those spots out before putting the modified thinset down under the Ditra? Or can i put the modified thinset right onto the plywood and have it fill in the gaps?

Thanks!

Reply

Roger

Hi Paul,

You can use the thinset to fill the gaps.

Reply

Jennifer

Hi Roger,

Your site is a God-send, and I’ve been returning to it throughout the investigative stages of our remodeling project …

We are about to retile our foyer (remove existing 12×12 ceramic tile and install new 12×24 porcelain tile), which is at grade level and on cement slab (split-level home). Only one contractor has recommended an underlayment (he uses Ditra), while the others say it’s not necessary because our existing tile/grout shows absolutely no signs of movement — no cracks whatsoever. Do you think the Ditra would be overkill in this case, or is it still wise to install it?

Many thanks for your advice!

Reply

Roger

Hi Jennifer,

I would use the ditra. Why not have the added guarantee that it WILL NEVER crack, rather than ‘well, it shouldn’t crack’? :D A little protection now takes all uncertainties off the table.

Reply

Don Youel

Hello Roger,

Have you seen the new Ditra designed to allow installation of electric floor heating cable within the same profile as the Ditra? The cable is laid in “slots” the Ditra, saving about 3/8″ of elevation and not have to deal with screwing fasteners in to secure the cable. If you have seen it, is there are problem with the roll out of the new product? I an not find in Toledo – or not looking in right place.

Tjha

Reply

Roger

Hi Don,

Ditra heat is the product you’re speaking of. Yes, I have seen it and used it, the best way to do in-floor heat hands down! There is not necessarily a problem with the roll out of it, it’s just really new. It was only released to the general public about two months ago. If your distributor were to order it they would have it within a week I would think. Mine does.

Reply

Chuck

:rockon: Thanks for the great information you provide and the non-snooty way you present it. I’m in the process (is 4 months concidered one process or 4??) of installing a 4X5 walk in shower in our master bath and your posts have given me some peace of mind since I wasn’t always sure i’m doing it the right way.

Reply

Jinny

We are laying 3 inch hexagonal tile with expandable grout. We have about 1/8 inch difference in one part of the room. This is due to adding the hallway into the existing bathroom. Our contractor has put down some floor leveler over the plywood subfloor, but I am still nervous. I can run my finger over the difference and feel it. In your opinion(and remember you are speaking with someone who you have to speak to in layman’s terms), how should we do this? We live in a small community with not too many choices on who to speak with about it.

Reply

Roger

Hi Jinny,

I would love to help, but you’ll have to explain to me what you mean by ‘expandable grout’? I have no idea what that may be. If he used floor leveler then it should be flat, but it may not be perfect, this is usually compensated for as the tile is installed.

Reply

Jinny

My contractor called it expandable, possibly just for a term I would comprehend. He said it had some flexibility to it, for use on older homes with floors that weren’t perfect. Your quick response is so much appreciated.(loved your article, by the way!) I can now sleep tonight, not worrying about it being done wrong tomorrow. Thanks again, Roger.

Reply

Brantley

Roger, I’ve incorporated a concrete slab back porch to an existing closet in a remodel to enlarge the bathroom. Now I have two different “subfloor” materials, one concrete and the other 1″ plywood that have a butt joint.
1) Is using Ditra the best way to prevent a crack in the tile where the two subfloor materials are and may move differently?
2) Next, do I use modified or unmodified thinset for both concrete & plywood subfloors? (see your comment below)
3) Last, is thinset the same as mortar?
Thank you

“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).”

Reply

Roger

Hi Brantley,

1. Yes, in my opinion it is. You do, however, still need to install a soft joint over that transition through the tile installation.

2. I would use modified for both.

3. Thinset is a type of mortar. I would need the reason for that question to be any more help than that. :D

Reply

Sasha

A contractor suggested using underlayment on top of some existing tile to re-tile my bathroom. The bathroom sits on top of an unfinished basement. The house is 30 years old and I wanted to know if that is the proper way to install underlayment or should I tell him to take up existing tile?

Reply

Roger

Hi Sasha,

There are membranes that can be placed over tile for an installation, like greenskin or tavy thin-skin, but not regular underlayment. That word encompasses a lot of things. If he is speaking of something like regular backerboard then the tile needs to be removed.

Reply

Andy

I am going to have 16X16 Travertine stone tile installed over a 6 inch concrete floor. My Condo Board requires an STC of 73 or > and an IIC of 72 or >. I have and read all of the literature on Ditra XL but can’t figure out how to get to those numbers. Can you make any recommendations ?

Thanks

Reply

Roger

Hi Andy,

If you call Schluter technical line they can give you all the acoustic and impact rating classes for their products. I’ve not had any need for those so I don’t know what they are.

Reply

Scott

I need to install 1200 ft ^2 of tile in a basement with several expansion joints. The Ditra seems best but it is very pricey. I have been told I can “tape over these joints” and use latex additive in the mortar / grout. The basement is very stable. Five years no visable cracks, so the joints are either doing their job or the floor is very stable or both.

Is there a product capable of this “taping”, what is it and how should it be installed? I am assuming it would be cheaper than the Ditrs since it would be so much less area, the tappered surface at the joints might also be a difficulty?,

Thanks.

ST

Reply

Roger

Hi Trevor,

You can with a sheet crack isolation membrane. Noble has one as does mapei. I believe most manufacturers do. You also need to carry those joints up through the tile with a soft joint.

Reply

Teresa West

Our contractor suggest that we use Ditra for our bathroom. However, we have chosen to use the 1″ hexagon black and white mosaic floor tiles. The Schluter official information says not to use Ditra for this small a tile, but when we were at the tile shop, they said that it was okay as long as we use a modified thinset and just allow for the extra time to dry. They even called the Schluter rep and he said that this would work. Reading various sites, other folks have suggested pre-filling the holes (I think skimming?) and letting dry overnight then tiling as usual with the unmodified thinset the next day. Finally, other people say just not to use the Ditra. What would you suggest?

Reply

Roger

Hi Teresa,

I would not use ditra for any tile under 2″ square. The problem is not the thinset curing correctly, or type of thinset, or anything like that. It’s the size of the cavities in the ditra. If you have tile smaller than 2″ square you may have edges of the tile which only set on the raised ridges and aren’t bonded into the cavity. A 1″ tile can be centered directly over the cavity which essentially leaves every edge of that particular tile unsupported.

Reply

ann

Hello: I have gotten 3 estimates to lay stone tile. Each contractor wants to use a different underlayment. One wants to use 1/4 inch Durock with thinset, one wants to use Fiberock, and one wants to use Schluter Ditra. What are your thoughts on this? I am leaning towards the contractor that wants to use the Schluter Ditra, but would be interested in your opinion. Thanks…

Reply

Roger

Hi Ann,

Any of the three works just fine. Go with the contractor you feel most comfortable with. If you want a specific underlayment, like ditra, then go with that one.

Reply

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