Ditra/Mud?

[Bri]

Hi
Here's one for you.....I've got a floor to tile, that even though it is solid, and up to spec, has some nasty dips and holes, and other low spots(like an ocean). What's to stop a guy from laying Ditra over the whole thing, and then mudding the low spots level? In other words, there will be spots that are mud and spots that are Ditra. Yeah, I know I could fix the floor first and then the Ditra, but why not the other way around? You can stucco over it..why not mud?

thanks ;)

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[Bud Cline]

I think I agree. Why not?

Assuming of course that the DITRA'S makeup will handle the "gains & losses" that will occur when trying to make it conform to the highs and lows of the existing subsurface.

[Rob Z]

I've talked to my Schluter rep (Larry Horton) about this topic before. He told me that Schluter's position is at all times Ditra should be as close to the tile as possible...meaning that any slc, mud, feather patch, heating mats, etc should be underneath the Ditra. He said that the Ditra works best with tile bonded directly to it.

[chip]

It seems to me that the membrane wouldn't conform completely with the dips, valleys and or oceans.

what you would have is the start of folds, bends and other un-natural configurations of the material, and then it would be fighting to return to it's normal configuration. Which is flat.

And when it did this wonderous, un-coupling this time, there would be voids over the dips, valley and oceans.

And by the way, I'm a little upset with you calling all the others "Dips"!!! I didn't know you knew them that well;)

The Chipster

[John Bridge]

The second highest supreme dip will now speak, Gobis being the number one dip. :D

I would not do it, Bri. I agree with Rob and Chip (and Larry Horton) that the Ditra is designed to work directly under the tiles. Besides that, thin set is much stronger in those little squares than deck mud could ever be, and your mud would not be re-inforced, either.

[Bud Cline]

Bud Cline: "Assuming of course that the DITRA'S makeup will handle the "gains & losses" that will occur when trying to make it conform to the highs and lows of the existing subsurface".

What's this? I don't even get an honorable mention?

[Bri]

Gentleman ;)
I get what you are saying..the rolls in the floor are over a large area, so getting the Ditra to lay flat isn't a problem...but I think you are all probably right....interesting though, that you can put in on walls with a scratch coat and stucco....the fact that your aren't walking on the walls must be the difference...but anyway, thanks...I'll fix the floors first.:)

[John Bridge]

Sorry Bud, but whether the Ditra conformed to the shape of the floor was not very high on my list. :)

[Bud Cline]

well ya but John

[Rob Z]

"...that you can put in on walls with a scratch coat and stucco..."

Bri

I didn't know about this...Ditra can be used with stucco material floated on top of it? Tell me more! (I don't plan to do any stucco work, I'm just curious). :)

[Bri]

Well Geez...maybe my idea wasn't so bad...this is from their site.

" Schlüter®-DITRA is also suited as a support matting for covering materials such as stucco, plaster, or screed."

Be afraid...be very afraid!;)


ps
I should also mention that I already tried this on a tub deck...I needed to lift the surface up to the top of the tub, so I put Ditra on the deck, and mud on top of that..between 1/2 and 1 inch...and then the tile. Seemed pretty sturdy the next day..so far so good.:)

[John Bridge]

Hell, with that much mud, why didn't you just staple down some lath?

I'll answer that. You had Ditra on hand and didn't have any lath? :)

[Bri]

Lath 10 cents a foot....Ditra $2.00 a foot...hmmm...well at least it's somewhat waterproofed now.;)

[JC]

It seems to me that you guys are probably right about the Ditra being as close to the tile the better..but I would be somewhat surprised if it really made that much differance to
actually effect anything.

Perhaps the biggest reason I find for leveling BEFORE installing ditra is that any bonding problems or bs can be under the Ditra in the "safety zone"...or less crucial part of the system.

But probably the biggest reason I would do it that way is becuase it is easier to get a level floor if the patch is under the Ditra..and the Ditra can take up the remaining slack sorta.

I do this with Membranes also..get a low spot just freehand some thinset on the floor to basically where you want it, slap down a membrane like TS and then smooth the membrane with a trowel to get it flat and level...works pretty good and quick. Saves from worrying about little imperfections and trowel marks that need scraped etc..
Of course with the Ditra allowing the patch to dry first before installing the Ditra would be better I would think..never really tried it the wet way with Ditra.