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Razkal719 t1_iug8wrf wrote

The ONLY mortar for putting down Ditra is regular unmodified thinset, A118.1 Because it has to cure purely from the chemical reaction of the cement as it will be covered by the plastic Ditra. Don't use anything with "crack preventive" or "modified" in the name.

As to your floor, as long as the glue is well and truly stuck to the concrete and doesn't have any large bumps or trowel lines you can lay the thinset and ditra on top of it. Looking at your picture, I'd go at it a bit with a bladed floor scraper, but no need to get too picky. The Ditra is an isolation membrane so it'll separate the concrete from the tile bed.

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rossmosh85 t1_iugb2xh wrote

This is not true. Schluter all set is a modified thin set which obviously can be used with schluter ditra and kerdi products.

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WittyWest t1_iugilf1 wrote

Plus... You get the warranty with all set. This is the route I'd go. You can grind the rest of the glue down or use a primer over the top as well. Not that it's totally necessary but it's an option.

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Mp32pingi25 t1_iugkzr4 wrote

He’s not wrong either though. You shouldn’t use “modified” thinset unless it’s All Set

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itriedtoplaynice t1_iui3rtv wrote

The ditra install manual states unmodified A118.1 for concrete substrates

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Razkal719 t1_iugoky8 wrote

You can use modified to put tile onto the ditra, but NOT to put the ditra onto the substrate.

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Zenit_IIfx OP t1_iugaqyl wrote

If the regular thinset will bond to the glue (likely white mastic) without fail, I will go this route if I can get the floor scraped up some more w the blade on a pole. Thanks!

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Dildo5000 t1_iugtuq8 wrote

You realize you need to level your floor right. Not only do you need to remove the glue. Grind and scratch your concrete. But is very, very, very likely not flat enough for tile. Which means you’ll be pouring an SLC over your freshly ground concrete floor.

Do it right and don’t be a hack.

Also you need to pull your toilet off. Sink cabinet. And baseboards.

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[deleted] t1_iuhiwfu wrote

[deleted]

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itriedtoplaynice t1_iui3mm4 wrote

The ditra install manual states unmodified thin-set mortar A118.1 for concrete substrates

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PhillipAlanSheoh t1_iuidvmt wrote

Shit - my bad. I missed the concrete part.

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itriedtoplaynice t1_iuie9ni wrote

I only looked because I used ditra a couple years ago and wanted to make sure I didn't fuck up my bathroom lol

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