Ditra [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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07-26-2019, 06:57 AM
Can Ditra be put down but the tile not put on top for a couple of months.
There will be very limited traffic. This is on concrete in which an asbestos floor was just taken out, in basement. Want to make it watertight. Thanks

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Jeff Bingham
07-26-2019, 07:09 AM
Sure. I'd skim it out with a modified thinset so traffic doesn't crush the grid.

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Tool Guy - Kg
07-26-2019, 07:58 AM
Not sure how modified is any better than unmodified, as neither will stick to the non-dovetailed waffle portion. But that's your choice. Especially if you want to pre-fill the waffles, I'd want to protect it from foot traffic. Even a cheap sheet of lauan for $10 ripped in half to give yourself a runway would help. And lauan would lay relatively flat compared to most other plys.


Jeff Bingham
07-26-2019, 08:22 AM
I think it dries harder.

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07-26-2019, 08:27 AM
You can use whatever you want, but schluter specs unmodified, or THEIR own mortar, at least in the USA.

4. Tile can be installed over DITRA and DITRA-XL immediately; no need to wait for the mortar to cure. Fill the cut-back cavities with Schluter-SET, Schluter-ALL-SET, Schluter-FAST-SET, or unmodified thin-set mortar and comb additional mortar over the matting using a trowel that is appropriate for the size of the tile. Solidly embed the tiles in the setting material. Periodically remove and check a tile to ensure that full coverage is being attained. Back-buttering is a useful way to help ensure proper coverage, particularly when installing large-format tiles (e.g., 12" x 12" (305 mm x 305 mm) and larger).

07-26-2019, 08:40 AM
Welcome, Mondo. :)

I would not recommend you do that. If you don't intend to tile your concrete floor for a couple months, I'd recommend you protect the concrete from excessive contamination until you're ready for tile and install your Ditra then.

Even if well protected, and even if filled with mortar, I'd worry about damage to the Ditra, including working some of the mortar loose in those waffles.

Not sure where Jeff is getting his information about the "hardness" of thinset mortars, but, as Goldstein points out, you're not adhering anything to the top surface of the Ditra anyway and an un-modified mortar will work as well as a modified mortar in that application. The modified may be a little easier to work with and even Schluter will accept the use of such mortars in pre-filling the Ditra surface.

My opinion; worth price charged.

Jeff Bingham
07-26-2019, 09:07 AM
Just my opinion based on real world experience fellas. No need to over think this...

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07-26-2019, 09:44 AM
thanks everybody. I like the luan idea. I should have been more specfic. I will be the only one walking on it and it shouldn't be more then a half dozen time till it will be tiled. I just didn't know if it would be better to tile on the Ditra before it was completly cured to the concrete floor? Again just wanted to get it waterproofed right away. Might not put tile down for a couple of months.

07-26-2019, 11:24 AM
You know you have to Kerdi band the seams to make it waterproof?

07-26-2019, 08:42 PM
Even unfilled walking on it 50 times won't bother it if your under 200#.

07-26-2019, 09:04 PM
You wanna give us some background on that statement, Teddy? Or perhaps at least some rationale?

I weigh only 160 pounds and I certainly wouldn't wanna be walking on my unfilled Ditra 50 times.

07-26-2019, 09:44 PM
I weigh in at 174# and I see no deformation or damage when I walk on Ditra or ditra heat. I even prefilled my ditra heat and only had two cups come off. Both when I was trying to get dried blobs of thinset off. The blob adhered and pulled the filled cup off. If you're a peg-leg it may be different but if you're putting 200# on a foot with 16 sq in plus contact area I am sure there is not going to be permanent deformation. But I can test a square with a weight if you want.

07-26-2019, 10:09 PM
Thanks Lou. I did know that. So what I am gathering is the Ditra will be fine.
Again thanks everybody for your help.