Ditra-Set Thin Set Article

[John Bridge]

Hi folks,

I've just published a new article on Ditra-Set, the preferred thin set when using Schluter Kerdi and Ditra.

http://www.johnbridge.com/ditra_set.htm

[Rd Tile]

So, you've switched from using that other slightly modified brand.

Nice article.

[davem]

Good article John.

[John Bridge]

RD, until recently I couldn't get Ditra-Set, so I used VersaBond, and I will still use VersaBond when I can't get Ditra-Set for some reason. It works fine. After all these years, though, it's really nice to be able to satisfy Schluter by using dry-set, a really good dry-set. I am right now in complete compliance for a change.

[simpsonb]

Good article John.

I'm happy to say that I love this stuff. I'm able to procure Ditra-set from a local distributor now and used it to apply 1/2" 18x18 travertine to my new Kerdi shower and this stuff sticks like glue! I was originally going to use Versabond. I used a 1/2" square notch trowel (I have very flat walls) and once it suctioned to the wall, I really had to pry hard to get it to release in a few instances where I needed to adjust. I burned in both the stone AND the Kerdi membrane to ensure a good bond.

I followed the directions and let it slack for 15 minutes and then stirred it again. It has a great pot life and trowels like butter. I don't know what they put in this stuff but it cures like a rock and sticks like crazy.

I wish the big box stores would carry it though...

[organic_donna]

simpsonb,
Did you install it over plywood or concrete? I am getting ready to install Ditra over concrete. I plan on using Ditraset with additive under the Ditra and Ditraset alone over the Ditra. I know that's not what's called for but was told that method worked well.
Donna

[jadnashua]

Why would you take someone's word other than the manufacturer on how to use their products?

[organic_donna]

Because I trust the people that actually do the job every day more than the manufacturer who tests the product.
Donna

[simpsonb]

I have not used Ditra-set with Ditra yet, only Kerdi in the shower walls so far. I plan on using Ditra-set over the Ditra on the floor when I do it. I'm putting down Suntouch radiant heat mats over 1 1/2" total exterior grade plywood and then Ditra and then my stone floor.

I don't know about using Ditra-set between Ditra and concrete, I'd have to refer to the mfg specs myself. I would imagine you would have to use a modified thinset over the concrete but I'm not sure. Anyone?

[Shaughnn]

Donna,
The additive is only used for applications over plywood. For installing DITRA over concrete, please follow the manufacturer's instructions. It seems obvious to me that your "professional advisor" is misquoting the manufacturer's instructions to you and setting you up for a possible disappointment.
Shaughnn
PS: I wish the DITRA-Set was available in gray.

[organic_donna]

Shaughnn,
This is the site where I've read that some installers prefer to use a lightly modified thinset under the Ditra matt even with concrete.
Donna

[organic_donna]

http://www.johnbridge.com/vbulletin/...ighlight=annie

Check out what Brian said about using Ditra. He is not the only one that said he uses a modified thinset under the Ditra, there are other posters.

Donna

[Kirk Grodske]

organic_donna,

Please note on that referenced thread one person said to use unmodifed and one person said to use slightly modified (Versabond). So these two opinions cancel each other out. Better to go with the mfg's instructions. They are the ones offering the warranty.

You can use a 4 inch grinder and scarify the floor with that. Or use a layer of Ditra which will act as a de-coupling layer. You can get Kerdi Band via mail order in a day or two, so I would suggest doing that.

Some people call the cement of the Slab on Grade a "sub-floor", but that is really using the term incorrectly. Ditra is not normally used on cement, unless there is some concern about cracking or moisture. If there is some residual cutback on the floor, some will recommend a modified thinset there, and then unmodifed on top, under the tile.

[jadnashua]

Originally, the owner and author of this article was the one that used Versabond with Kerdi, etc. He wrote this article stating that he's changed his ways...a quality dryset mortar is what the manufacturer specifies, they've tested the stuff in more ways than you'll ever do, have thousands of installations in both the US and abroad, and know their product. Trying to second-guess them is not a good idea. Ditraset is a good product that works, maintains the manufacturer's warranty, and is what they recommend. Using something else, when that is available is somewhat foolhardy. Now, if you can't get Ditraset, there are other quality dryset mortars available that would work as well.

[Bill Vincent]

It seems obvious to me that your "professional advisor" is misquoting the manufacturer's instructions to you and setting you up for a possible disappointment.

Nope. Her professional advisor said straight out that Schluter calls for unmodified thinset under the Ditra over concrete. but that her professional advisor uses the modified thinset, anyway, because he trusts the bond alot more. He's seen way too much tile set over concrete with unmodified thinset, when he lived down in Florida, that's lifted afterward because of not enough grab.

BTW-- John-- I read the article the other day, and thought I left a comment then, but apparently I didn't. Great article!!