Another Ditra Discussion

[cx]

Mmmmm. How'd we segue into "caulk and expansion joints" from the discussion of uncoupling membranes, Jeff?

[John Bridge]

As to tests there is the test of time. Ditra was/is the very first product on the market claiming "uncoupling" properties. I've used it since 2002, and it was around before that time. I've never had a floor failure where Ditra was used, and I'm certainly not alone.

I've not had occasion to use the other brands, but I'm betting if they replicate Ditra they're going to work.

[Dave Gobis]

I have firsthand knowledge and experience on this issue having been involved since day one. Probably my fault it did get into the handbook when it did, rewrote the submission for Peter. The story is lengthy, and a team of horses couldn't make me get back in it. All I will say is marketing reigns supreme.

[jeffnc]

Originally Posted by cx

How'd we segue into "caulk and expansion joints" from the discussion of uncoupling membranes, Jeff?

Read all the posts.

[jadnashua]

Ditra works IN PLANE, and has little to do with vertical movement. It helps when the tile entire assembly can move independently of what's beneath it, as can happen as thermal expansion or contraction occurs. It does essentially nothing for vertical movement, or uneven expansion/contraction you might experience from say solar heating a small section...that's why you may need expansion joints. Seasonal movement from say the plywood absorbing and releasing moisture causing dimensional changes can be handled by Ditra.

It's tough to get a surface you can install Ditra to, that you can then control expansion in to reliably do a repeatable test...those structures just don't exist right now, so replicating the test would be both tough to design, and expensive.

[Tiger Mountain Tile Inc]

I was looking over data sheets for different uncoupling membranes recently. It seems to me that some manufacturers are inferring their uncoupling membrane meets A118.12 but, under closer inspection, they only list some of the tests that were passed.

So, by my eyes, it doesn't pass the whole standard. Only components of the standard.

In fact, there was only one membrane that I looked at that claimed to pass the whole standard. But maybe I'm not reading things correctly.
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Not to nitpick, but it would be nice if there was a brief editorial that explained that this thread was split off from another thread and maybe add a link to the original thread and post# in paragraph 1?

I know, easy for me to suggest...

[cx]

Post #14 was s'posta 'splain that, Jim, which is when the salient posts were separated from the original project thread in the Advice forum. That thread had absolutely nothing to do with uncoupling membranes, which is why it's not linked here and why the discussion was moved here.

I think you're reading things correctly. And one uncoupling product I think is actually listed as meeting A118.12 has some rather confusing language, to my thinking, in some parts of the listed "Advantages."

I expect one day there will be an industry standard for uncoupling membranes. I'm hoping someone will send me a copy to wherever dead guys get their mail.

[John Bridge]

Whatever the problem is, if there is a problem. can be attributed to Gobis.

[Dave Gobis]

I was lied to. Wasn't completely my fault but I drove it pretty hard. Having that and foam getting into the handbook did result in steps to prevent a repeat performance of singular products constituting a method. The precedent for all of this was when Wonderboard went into the handbook.

The reference to some using portions of the ANSI standard to legitimize or promote their product(s) is wholly accurate It is just like........, yeah, sure.

[cx]

Originally Posted by Gobis

The reference to some using portions of the ANSI standard to legitimize or promote their product(s) is wholly accurate...

And some of it is so blatant that there is no other explanation than it being intentionally misleading. Unfortunately, it probably works.

[Dave Gobis]

Yup, that's why Technical Services is overseen by the Marketing Department.

[e3]

hold my beer.!

[cx]

Is there a conflict, Eric?

[Dave Gobis]

If I said " the majority of" would that make it better Eric?

When I was doing classes at CTEF one of my found memories was getting fired by a tile related product manufacturer. Their stated reason was we spend months teaching them how to sell the product only to have you destroy it in a matter of days. They told me to tone it down or they were pulling out. I said thanks for the past business and good luck in your future endeavors. They were a pretty strong supporter but I am not going to spread BS on their behalf for $$.

[Dan Marvin]

Well, you've all teed it up nicely for me to jump in and get my ears pinned back but what to heck, I'll give it a go.

I was an early objector to uncoupling as a concept. I was convinced that it was marketing mumbo-jumbo and there wasn't a significant difference between uncoupling and crack isolation. My opinion started to change when I was at MAPEI and was able to look at the stacks of Robinson tests they've conducted and tear apart assemblies after they were tested. The 'air space' and fleece in uncoupling membranes really do allow for deformation (ie, uncoupling) that a crack isolation membrane in itself does not. I pushed hard for MAPEI to introduce an uncoupling membrane not realizing that a few years later I'd be working for Schluter. Now they have several.

Now that I'm at Schluter I've been able to look at all of the testing they've conducted as they work on an ANSI standard. Remember that A118.12 is a test specifically designed to evaluate crack isolation membranes. Section 5.4 of that standard (where a large horizontal crack is quickly created in the substrate) is difficult for uncoupling membranes to pass and Ditra is no exception to that statement. That's not how cracks tend to occur in the real world but that's how crack isolation membranes are tested and where uncoupling doesn't test well.

The answer that several of you have alluded to is to develop a standard that really tests the concept of uncoupling. That effort has been underway for a long time, more than a decade. Trust me, the MMSA committee working on it (and the ISO committee working on the international standard) want to get that effort across the finish line. I'm hopeful that in 2023 we will be able to move it out of MMSA and on to ANSI for a vote there.

So, in the meantime I guess you'll have to take my word for it as a former skeptic and competitor. Uncoupling is a real thing, it does benefit tile assemblies especially with today's emphasis on speed and cost avoidance in construction. It does what we say, even if we don't yet have an ANSI designation to prove it. And no, I don't report to the Marketing department