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Schluter DITRA Over Wood in a Bathroom

Prevent Broken Tiles

As Seen On
Schluter DITRA

Cracked floor tiles stink…REALLY BAD

There’s a simple solution: Schluter DITRA

It goes down on top of wood or concrete subfloors.

Your tile then goes on the DITRA.

Today we’ll show you how to install DITRA on a wood subfloor.

PLUS you get to see a pro tile installer do it.

This tutorials is gonna make your tile installation way faster!!


Why Use Schluter DITRA 

Tile floors…there’s no doubt they make homes look nicer.

But what’s not so awesome are broken tiles.

Broken Tile

This is a HUGE issue if your home settles over time.

Guess what,

all homes settle!!!!!!!

DITRA  solves this problem?

The best part is anyone can install it.


The Benefits of DITRA

DITRA is way easier to install than cement board.

First, it’s light.

Second, it stops tile and grout from cracking.

Third, it can waterproof the wood subfloor.

Waterproof Any Floor

If you’re afraid of mold in the bathroom DITRA will help.

Steve and I will show you how to install DITRA today and make it 100% waterproof.

Here are the supplies you need

So what’s the first step when installing DITRA on a wood subfloor?


Know the Framing of Your Home

Schluter DITRA has the best technical support…

I’ve called them in New York like 2,989.384 times.

They answer the phone every time!!

Schluter also has the best installation directions.

Hey, they’re German and you know what that means…DETAILS my friend.


Know the joist spacing of your home before installing DITRA.

Here’s the basic rundown of how to use DITRA for ceramic or porcelain tile

  1. 16 inch on-center joist spacing with single layer OSB or plywood subfloors
  2. 19.2 inch on-center joist spacing with single layer OSB or plywood subfloors
  3. 24 inch on-center joist spacing with double layer OSB or plywood subfloors
  4. 24 inch on-center joist spacing with single layer OSB or plywood subfloors

Each configuration has specific guidance for

  • subfloor requirements
  • substrate preparation
  • movement joints
  • thin-set, grout, and more.

Basically you can install DITRA over

  • plywood
  • existing vinyl floors
  • structural plank subfloors
  • concrete
  • and heated floors.

BUT again, this tutorial is just for wood subfloors.

All the specifics for DITRA installation are in the handbook or on Schluter’s site.


ensure subfloor panels are level and properly fastened to the joists.

Inspect the floor for protruding nails or screws (fix squeaks before installing any flooring).

Subfloor Secured

AND if your subfloor is tented or butted together super tight,

you’ll want to take care of this issue.

The big problem with tight subfloor seams is they don’t allow for expansion and contraction.

Hence the need for 1/8″ gaps between seams.

Let’s dive into the installation process.


Install Schluter DITRA Over Wood Subfloors

Once your subfloor is good to go it’s time to install the DITRA.

Mix up modified thin-set.

Mix Thin-set

Thin-set should be mixed to a fairly fluid consistency.

BUT should still hold a notch.

How do you know you have the right modified thin-set?

Look on the bag for ANSI A118.1.


Again, modified thin-set is what you want between DITRA and the wood subfloor.

Measure the floor dimensions and cut your DITRA.

You can cut DITRA with a utility knife.


Dry fit the DITRA


Clean and dampen the wood subfloor.

This creates a solid bond between the thin-set and DITRA.

Clean Subfloor

What trowel should you use to apply thin-set to the wood subfloor?

Check it out, we’ve got you covered

  • 1/4″ x 3/16″ V-notched or
  • 5/16″ x 5/16″ V-notched trowel or
  • DITRA trowel which features a 11/64″ x 11/64″ square-notched design

How’s that for detail!!

Apply the thin-set to the wood subfloor.

Notches should all run in the same direction.

Apply Thin-Set

Embed the fleece side of the DITRA in the thin-set.

Leave a 1/4″ gap between walls and the bathtub.

Use a rubber grout float to push the DITRA into the thin-set

Rubber Float

Lift up a corner of the DITRA to check for thin-set coverage.

Your goal should be 100% coverage…we had a few bare spots here and fixed that issue!!


You can abut end and side sections of adjacent DITRA sheets.


Watch our step-by-step video for all the juicy details 🙂

The beginning shows you why I like DITRA versus cement board

Now for the waterproofing step!!


Make Schluter DITRA 100% Waterproof 

First of all,

isn’t DITRA way better than cement board?

I’ve put my back out many of times lugging cement board.

No more of that.

Not to mention that you have to attach cement board panels using screws.

Each screw represents a leak point for water.

So how easy is it to waterproof DITRA?

At the joints, fill the cavities with unmodified thin-set mortar.

Make about an 8 inch band of thin-set centered over DITRA joints.

Fill Joints with Thin-set

Comb additional thin-set over the joint using an approved trowel.

Center the 5 inch wide KERDI-BAND over the joint.

Center KERDI BAND on Joint

With the flat side of the trowel, firmly press the KERDI-BAND into the mortar.

Make sure to fully embed the KERDI-BAND and remove any excess mortar and air pockets.

Embed KERDI into Joint

You can use this same method where DITRA meets drywall.

We used a 5 inch wide KERDI-BAND because if it’s centered, your base molding will hide it.

Check out the video for those details.

One of the worst spots for water damage is where your tub meets the tile floor.

Fill the 1/4 inch gap between the DITRA and tub with KERDI-FIX.

Fill Gap with KERDI FIX

Fill in the cavities with unmodified thin-set and embed the 5 inch wide KERDI-BAND

Embed KERDI Near Tub

Steve shows you the exact method in our video,

you’ll be a whiz at DITRA installation after today!

DITRA is the easiest way to waterproof your floor and prevent tile & grout from cracking.


What’s Next

We also have a great step-by-step tutorial on how to install DITRA-HEAT.

If you hate cold floors DITRA-HEAT is a fantastic option.

If you’re doing a bathroom remodel and want to simplify the process enroll into the Bathroom Repair Tutor Video Library

We show how to build showers (Schluter, Wedi, Curbless, etc.), install tile, upgrade basement bathrooms, and more.

The extra guidance is invaluable

Enroll Today



Jeff Patterson





  1. Faye says:

    Hi, I have a wooden sub-floor in my 1/2 bath that appears to be level to the naked eye. Do I need to use a leveling product before using DITRA, or will DITRA take care of any minor inconsistencies? Also, I think I need to pull out vanity, baseboards and toilet, install DITRA and then tile entire bath before reinstalling new toilet, vanity and baseboards. Is this correct? I may just surprise my husband by remodeling our 1/2 bath by myself! Thx!

    1. You’re right Faye, you need to remove the toilet, vanity and baseboards to install DITRA over your subfloor. And it should be as level as possible. DITRA is only 1/8″ thick so it won’t help with hills or valleys in your subfloor. You’ll have to sand those down or level them 😉

      Let me know if you have any questions along your journey, I’d be happy to help

  2. Dave C. says:

    Unlike Faye above, I know my subfloor is not level. When I pulled up the contractor grade sheet flooring, the leveling material came away in patches. So I removed it all to the plywood. The peel n stick tile I put down cracked within a year. Can I use a self leveling product under DITRA? I don’t think I can redo the subfloor.

    1. You can use self-leveling material under DITRA Dave, just make sure it’s completely dry before applying the thin-set.

      Sorry to hear about your issues, awe homeownership, the joys of DIY!!

  3. Elmer says:

    How about over vinyl tiles?.

    1. You can install DITRA over vinyl but make sure to follow the Schluter directions to a “T”.

      I’d personally recommend tearing up the tiles so as to inspect the subfloor for any damage.

      But if you’re sure the subfloor is solid, no water damage, and there aren’t other products under the vinyl…you could install DITRA over it.

  4. Ron says:

    Hi Jeff. Here, on the podcast, and in the videos it says to lay down MODIFIED thin-set. It also says to use ANSI A118.1. However, ANSI A118.1 is for unmodified thin-set (ANSI A118.4 is for modified). Also, the Schluter installation handbook also recommends using unmodified thin-set (ANSI A118.1) to lay down Ditra over wood. Am I misreading this?

    1. Ron says:

      Hi Jeff. I re-read Schluter’s install guide and you are correct to set the Ditra down it should use MODIFIED thin-set However, the standard above for MODIFIED should ANSI A118.11 (its currently listed as ANSI A118.1 which is for unmodified thin-set).

  5. Ken says:

    I am planning to put porcelai tiles on top of ditra. The Ditra will be on the vinyl over plywood. The installation manual says that I need to put a screw/nail through vinyl/ply every 4 inches that is about 9 nails per square foot. This is too much of screws. Is it really needed?

  6. Gilles Morin says:

    Is it better to put cement boards on wood floor first before installing Ditra?

  7. Joyce Brown says:

    I am really interested in your product but I have a question, how would you install this product if part of your design includes a radiant floor. Can/should the radiant floor be installed on top? If so is there a restriction of which type of floor install?
    Thank you

    1. Patrick Coberley says:

      Joyce, great news. Schluter makes a radiant floor system called Ditra Heat. It is an all inclusive system; mat, wiring, etc.
      Easiest install on the market.

  8. Ken Stevens says:

    What are the benefits of Ditra over the RedGard uncoupling mat? I see the Ditra installation uses both modified and modified thinset. Wouldn’t the RedGard be less complicated due to using all modified thinset?

    1. One way to cut down on the confusion Ken is to use Schluter’s ALL-SET. It’s a thin-set meant for both under and over DITRA. We like DITRA because it’s never failed us and the installation is very straight forward.

  9. Jane DIY ADDICT says:

    We use Schluter kerdi shower kit 72 x72 had purchase extra corners and also ditra heat , purchased extra band to join sheets. We also bought schluter thinset which is very expensive but we wanted the full warranty. It been a great deal of work and not as easy as it looks. Now planning out tile placement in all the shower area including ceiling and bathroom floor and walls…so much planning and time envolved

  10. Jane DIY ADDICT says:

    Can you make a video on tiling the shower ceiling with smaller mosaic tile and to keep in place and how yo cut these tiles on a wet saw without them falling off the webbed backing. This was one challenging job please help anyone else trying to do this, using schluter thinset. THANKS GUYS !

  11. Jane DIY ADDICT says:

    To Gilles Morin , no need to install cement over wood floor, please look on website. It will explain what is needed, even thickness of flooring needed. You can even send them a message or call they will reply

  12. Steve says:

    Can I use ditra over cement board like duroc?

  13. Tomas says:

    My toilet leaked and created some water damage into the lower floor. I plan on replacing the plywood subfloor in the entire bathroom before adding the Ditra floor.
    What kind and thickness of plywood do you recommend to use with the Shluter?

  14. Ning says:

    Do I have to tile over the Kerdi band where floor.meets wll or can I install pvc moulding?

  15. Brooke says:

    When I removed a cracked tile in my kitchen to replace it, the corner of the Ditra pulled up. Is there a way to reattach it or is it okay to go ahead and replace the tile?

  16. Vinod says:


    If the plywood floor in the bathroom is not level, do you recommend using a self leveling compound and then installing Ditra over it?

  17. Matt says:

    I’m considering installing a wood-like ceramic tile over existing wood flooring which consists of 2x wood plank subfloor (not plywood sheathing) with finish wood flooring on top. What is your recommendation to install Ditra over existing flooring? My initial thoughts include removing the existing finish wood floor, then install Ditra and modified thin set over the wood plank floor, and lastly unmodified and ceramic tile over Ditra. I’m interesting in hearing your thoughts before I begin my renovation.

  18. Patrick says:

    Hi, I just removed all of the old ceramic tile in my bathroom. Vanity and toilet have been removed, and the new tub has been installed. When removing the old tile, I realized the floor is not perfectly level, due to the old mortar. Can you recommend a self leveling product to use, before placing down the ditra? Also, would you be able to confirm that Mapei uncoupling membrane mortar (thin -set) is the correct product to use over the self leveling product that should be placed on the plywood subfloor? Additionally, can I use the same thin set on top of the ditra to fill in the waffles and cover the seems between the ditra?

    Thanks for all your help!!

  19. Roxanne McCallister says:

    We are looking at using Ditra to retile our kitchen. We have 16″ floor joist with a 3/8″ plywood, a layer of tar paper, then 3/4″ tongue and groove Drymax. I read over the Schluter PDF where it had the strengths of various types of tile listed as well as a lot of other data regarding the product. We were wondering what the maximum size of tile we can install is? We have been told that you can’t use tiles much larger than 16×16 with a wood floor and crawlspace. We weren’t sure this applied to the Ditra products or not. We found a 12×48 ceramic tile we fell in love with and I would like to know if that would be fine or would there be issues with it cracking?

  20. Christopher says:

    I just laid my ditra on my bathroom floor. I had to patch a piece of rotted subfloor and one corner of the is sitting Higher on the patch then the surrounding subfloor. Help!

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