Schluter-Ditra Universal Underlayment – The Undergarment Every Tile Floor Needs

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schluter-universal-underlaymentSchluter-Ditra understands that tile, being a hard, brittle substance, expands and contracts due to moisture and temperature related conditions, at a totally, different rate from whichever substrate material lies beneath, be it plywood, concrete, cement, etc. This can be a problem when using traditional, thin-set mortar bed applications, which bond the tile directly to the supporting structure. The result is usually cracked, ruined tiles. In order to ensure both layers can move independently, an additional layer in between the two materials, is a must-have. (And no, you can’t just lay any, random thing down. Just in case someone out there is thinking, “Huh. I don’t see any reason I couldn’t use this old comforter.”)  The Schluter-Ditra Universal Underlayment is the better option.  

Schluter-Ditra is an uncoupling membrane system designed specifically for tile and stone installations. The membrane provides a shear interface within the tile assembly, which allows the substrate (base) and surface (tile or stone) to expand and contract independently of each other. It’s made of a thin, polyethylene sheet composed of a grid of square cavities with a fleece anchored to its underside for stability. Installation is easy:

  • Apply a layer of thin-set mortar over the floor surface and embed the Schluter-Ditra, fleece side down, using a float or screed trowel
  • Fill any joints with thin-set mortar and cover with the Schluter-KERDI-BAND, centered over the joints to ensure
    Shluter-KERDI-BAND: Seal those joints!


  • Fill the cavities with unmodified, thin-set mortar and lay your tiles

(For some reason, I equate this process to building a sandwich; ergo the only thing on my mind right now is a loaded, Italian sub.)

The system is lightweight and easy to handle, supports heavy loads, is waterproof and acts as a vapor barrier. This is so important considering tile and stone are highly susceptible to water penetration.

Schluter-Ditra is available on Amazon for $489.99 plus shipping, (323 sq. feet.)

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About Liz

Liz is a professional, custom picture framer based in Central New York. She and her contractor husband are currently renovating their second home together. At the time of this writing, they are not on speaking terms. Her love of making stuff with wood and DIY home projects began by watching her Dad. (It was also around this time Liz's incessant use of "colorful language" took root.) She's an avid gardener, stellar cook and doesn't throw like a girl: an all-around rad chick.

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9 thoughts on “Schluter-Ditra Universal Underlayment – The Undergarment Every Tile Floor Needs”

  1. My question is what about deflection from additional tile/marble weight. Does this product claim it reduces cracked tile like Durock or Wonder Board cement panels?

    • Hi Troy, I’m afraid we don’t have the answer to that. I’d recommend you get in touch with the Schluter folks directly for detailed product spec’s and info. This wasn’t a hands-on review for us, so unfortunately we don’t have direct experience with it other than hearing some good things about the product generally.

  2. Used this myself in a bathroom remodel. It goes down real easy. Here are some things I learned along the way:

    1. The Kerdi-Band isn’t necessary unless you’re trying to create a watherproof seal. If you’re waterproofing the Ditra, you should also be waterproofing between the Ditra and the wall, otherwise, don’t bother with the band. I’d say this is only important it you’re putting this in an upstairs laundry room where you also curb the door way like you would a shower to catch a sudden flood of water before it has a chance to drain.
    2. Use the proper sized trowel. You’ll end up with a lot of trowels when doing a whole bathroom, one trowel for Kerdi, one for Ditra, one for big tiles, one for mosaic tiles…
    3. The grooves underneath don’t need to be filled with mortar. Only the scrim (screen) needs to be fully adhered to the floor with mortar. The grooves underneath stay hollow as this is the decoupling mechanism.
    4. Even though they recommend unmodified thin set mortar, John Bridge (of all things Schluter) forums have seen much success with Versabond from Home Depot. It’s only “slightly” modified. Schluter will not honor their warranty if you use it but for a DIY project, you take your own risk. I’ve used it myself both above and below Kerdi and Ditra and haven’t had an issue. Mapei Kerabond is the Lowe’s brand recommended.

    Highly recommended.

  3. Our Home Depot has a nice, small display in the tile section that mentions you can consult with customer service people as to what you’ll need for a project and order from Schluter-Ditra for direct-to-home shipment with no extra shipping costs. Seems like a good set-up between manufacturer and dealer for the consumer’s sake.

  4. Two of my best friends are high end tile guys, and they swear by this stuff. One of them did the slate floor in our bathroom and he used this. Just a thin scratch coat over the mud job, then this stuff, then we hot glued the radiant electric heat cable to the orange stuff, then mortar & the slate on top of that. Came out great, and not a single problem 4+ years on.

  5. Sure see a lot of this being used by good old Mike Holmes and now
    in other programs as well. Thanks for providing more background information on the product.


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