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Schluter®-DITRA Over Wood in a Bathroom (Part 1) – by Home Repair Tutor

Schluter®-DITRA Over Wood in a Bathroom (Part 1) – by Home Repair Tutor

Before I head inside, let me explain what
we’re going to be doing here. We’re going to show you how to install Schluter DITRA
on wood plywood. So in this video you’re going to get all the tips and tricks that
you need to do this yourself. And in the end, we’ve got a really cool offer for you if
you’re going to be remodeling your bathroom. So stay tuned until the end because I think
you’re really going to like what we have to tell you. All right, let’s dive into
the tutorial right now. We’re going to go ahead and install the
underlayment for tile on a wood subfloor. Since I’ve been using this process not only
does it make the floor waterproof, but it’s considerably faster and easier. And the technology
behind this product ensures that your tile isn’t going to be subjected to expansion
and contraction of the wood you’re going over.
Now there are some things you have to consider before installing any tile and knowing what
your joint spacing is, knowing the thickness of the wood that you’re applying it over.
Ideally, if it’s plywood you want to be at least ¾” thick. Now there are some engineered
specs. If you’re going out 24” on-center and you’re using stone, you’re going to
have to thicken that subfloor for deflection. But on a typical install, if you’re doing
porcelain tile, ¾” subfloor or standard 16” on-center joint, this product is going
to be perfect for you. It makes it very easy. It’s called Schluter DITRA. And basically
this is just an uncoupling membrane that I’ll be adhering directly over the plywood, and
then the tile will be installed over top of this. Thinsetting this to the floor, and then
thinsetting the tile to this. And the idea—there’s a lot of theory and technology and engineering
put into this product—but the basics are that this separates the plywood layer from
the tile and allowing just normal expansion and contraction of that wood to not transfer
through the tile. So it’s better than putting a cement board
down. These days if you put cement board down, you’d almost want to still put this over
top of it. But not only does this help keeping that transfer of expansion and contraction,
but it also is waterproof. I mean, what’s better than that? I mean you have your toilet
overflow or kids are making a lot of splash in the tub, having this waterproof gives you
confidence and peace of mind, and it’s not going to ruin anything below it. There’s
way too many times that I pull up a toilet and I see the wood totally rotted around that
whole area. Now granted it probably has to do with a lot of the toilet leaking itself,
but if you used a product like this that’s going to keep that from happening.
So there’s a lot of advantages of doing it. For me personally, it’s so easy and
light. I can cut it with a utility knife. I’m not inhaling any dust by cutting all
that concrete board. I don’t have to screw anything down; I’m just thinsetting it.
So it’s a very easy product to install. So there’s a couple of components that go
with it. It’s the actual membrane itself, and these come in all different size rolls.
For this little bathroom area, you can probably just get a 50-sq-ft roll and be fine. It comes
with the KERDI Band. This is exactly the same stuff that we used for around the tub surround
to waterproof the joints of the KERDI Board. So you want to put this over any seam in the
corners of the room and wrap that up the wall so that you have a nice, waterproof, tight
floor. And you want to use the KERDI Fix. This is primarily to fill the gap between
the tub and DITRA. So we’ll show you how to install that. And then I’d say one of
the very important aspects of this is using the right notch trowel. Schluter makes a trowel
specifically for DITRA. It’s 1164; it’s basically 3/16” square notch trowel. This
will make adhering this down to the subfloor the proper thickness. And another great thing
about it is if you’re using a correct notch trowel, not only do you get a nice, flat surface,
but you can immediately install tile over top of this if you wanted to or try to attempt
to install tile the same day you put the underlayment down. Most other products you’re just not
going to be able to have the time to do that, especially if you use cement boards. It’s
going to take you half a day to install that. And by the time you get to doing the tile,
it’s usually past the time you want to work. So we’ll go ahead and put this down. It’s
a great product, and we’ll show you how easy and simple it is to do yourself.
the first thing you want to do is just to dry fit this down. And the rule of thumb is
basically trying to keep a ¾” reveal between the edge of the floor and the DITRA. And Schulter
recommends this—and this is especially important to stay within their warranty—you want to
have an expansion joint between the edge of the floor and the DITRA itself. So when you’re
dry fitting, just keep that in mind; and that’s around all areas. Against the tub as well.
Keep a ¾” gap between the tub and the DITRA. Now I’m just going to rough cut this before
applying thinset. Okay, so the first you want to do after you
have your first piece dry fitted, is to make sure your surface is all clean. Take any of
the drywall mud that might be stuck to the floor. Anything that can possibly jeopardize
the thinset that’s going to adhere to the actual plywood. So make sure your surface
is clean and dust proof. I mean dust can actually keep that thinset from bonding to the the
plywood. And what you want to do to apply the DITRA
to your wood subfloor is using modified thinset. So make sure whatever you buy or whatever
you’re looking at purchasing, that it’s going to be modified. Now that’s what you
want to adhere down to the subfloor. And to keep that layer of thinset from immediately
getting dried out from the plywood—because plywood’s mostly wood, I mean it’s obviously
wood, but it’s dry. And as soon as you put down that thinset, you don’t want it to
suck the moisture out of the thinset too quickly. So just take a damp sponge; it doesn’t have
to be soaking wet. We’ll just wipe down your subfloor, in the areas that you’re
going to be putting this DITRA. So this will also take any dust off. You just do a quick
once over prior to installing the DITRA. Okay, so when I mixed this thinset, I made
it very loose. It wants to kind of fall off the trowel. You want to try to apply the maximum
amount of water to your thinset says that it can do because you want to have this very
thick. Just allowing it to spread this out and be able to adhere it to the DITRA correctly.
So I’m going to put a bunch out here. The first step like any tile setting is to
firm the thinset into the soft surface. So just taking the flat surface of your trowel
and just working it into the plywood. I usually just do an area of arm’s length in to get
that full area. A little more. So just get that layer thinset down, and try to comb everything
in the same direction. And then, make sure you have that ¼” reveal. I just have a
regular grout float that I use to apply pressure to it and put it in place. First time you’ve
done it, I mean you’re going to feel for it. If you use the right lodge trowel and
you just did what I did, you get quick coverage. You can see about 80% of this covered, and
that’s what you’re looking for. So just make sure you have good coverage.
We said 80% coverage in the video, but try to shoot for 100% if you can. That just ensures
that the DITRA is completely embedded in the thinset.
Okay, so with the right lodge trowel, using their DITRA trowel, you can walk on this afterwards.
It won’t indent. Sometimes if you kneel on it a little bit, you can in some areas.
But if you’re using the right lodge trowel, it’s not going to sink too much. And obviously
for floors pretty level, it’s meant to be walked on immediately afterwards. Do the same
thing on the… as you continue. You might be wondering what Steve is doing
here. He’s pounding in any loose ring shank nails. Always a good idea to do that.
Okay, so you just want to butt this straight up against the other piece of DITRA as close
as you can; it doesn’t have to perfect. But remain with that ¼” gap around the
room here. It’s a little tight around the corner here,
so I’m just going to take out a little bit of DITRA to get that ¼” reveal. And again,
you can just pull some of this out and make sure you’re getting the right amount of
coverage. Actually, I think we have a blind spot right there. So I want to make sure I
have…. Then you can just use whatever you have left,
too. I mean it doesn’t have to be a full piece. You can put as many pieces together
as you want. So in this little mock-up that we have here,
obviously we don’t have a toilet flange where we need the toilet. So since this is
the mock-up, and it’s just the basic product, we didn’t have that put in here. But really
that is just as simple as cutting around that flange, keeping that same ¼” reveal around
the flange. And then you’ll be able to use the KERDI Fix to go around that toilet flange,
and it’ll keep everything waterproof up the toilet flange.
Now obviously, I mean, this is waterproof to a point. If your toilet does overflow,
there’s obviously areas around where your bolts connect and everything that water can
get down and below the pipe. So this isn’t meant to necessarily be able to take a shower
in this room, but it’s going to keep the majority of the water from splashing out of
the tub to some basic water issues from absorbing into the plywood.
All right. So that is how you install Schluter DITRA on a wood subfloor. This is actually
a part 1 of 2 video. You can watch the second video right here, and that will show you how
to completely waterproof the DITRA in a bathroom. Now here’ what I wanted to tell you about.
We have a free video series for you if you’re going to be starting a bathroom remodel. You
can check that out right here, and we’ll show you how to demo a bathroom, put in a
new tub, put in the plumbing, and so much more. So again, check that out right here.
But for today, if you have any questions about this tutorial, ask them down in the comments.
So again, ask them down in the comments; we’d be more than happy to help you out. And as
usual, you can always click the subscribe button if you want to watch our videos over
here on YouTube. They come out every single Tuesday.
So that’s it for today. I’ll see you in the comments. Take care. Have a good one.
Believe it or not, it’s January in Pittsburgh, but it’s 60∞, right Kate? No better time
to practice soft ball.


The industry standard is not to install tiles over wood because wood is porous and the thinset dries too fast for a good bond. Why would that not apply to thinset for Ditra? I for one prefer to use glue. Makes more sense to me.

I always got full cover very easy when I apply underlayment sealer over the plywood before thin set and Ditra, let me know is it the right way doing it or not but seem working fine, no call back.

While i think Ditra is a very good product, I give suspicion to it's marketing. Specifically the trowel 'THEY RECOMMEND'. 11/64!!! Come on. Rather than rely on the most commonly made owned and used 1/4" or 1/2" , they market their own. Might just as well go out and find a cheap 3/8" trowel or use the 1/4". Even in their 'native' metric system it doesn't apply to an exact mm standard. In this case a hair over 4mm. A reputable company with a good product shouldn't be nickel & diming their customers. Just my opinion.

I have watched several Schluter videos… on all the Kerdi membrane videos they say to use “non-modified” thinset or cement. In this Ditra video you stress using modified thinset. Is that correct?

I actually just laid this Ditra down in my bathroom. I used your video as a guide although I ended up having a fairly lumpy Ditra after install for some reason. It's very minimal though. I used the recommended trowel v notch too. Any idea if this will be an issue when I go to tile the floor now? Thanks.

DYI here. Completely redoing our 8×8 (not exact) hall bathroom. walls are dwn to the studs and just redid the plumbing to accommodate the new layout. New subfloor is 3/4" Advantech. It is not perfectly level (not terrible) and some joints are 1/8" higher/lower. Using 1/4" Ditra (16" off center joist). to accommodate the transition height. My question is. Does the subfloor need to be perfectly level and do the joint heights need to meet perfectly? Thank you. Great videos.

Can you use ditra under 12” marble tiles? On a wood subfloor? What is a standard subfloor for marble and natural stone like travertine? This is for three bathrooms. Thank you!

Bought ditra 18 years ago. Nobody knew what I was talking about, salesman at HD never heard of it. Called schluter direct, had is shipped to HD, salesman learned something. Ditra is awesome.

My subfloor is layered tongue and groove 100 year old subfloor plus 3/8 ply we added to smooth it out. It totals at least 3/4, is this ok, or do you have to use 3/4 ply?

Good video, I am doing my basement bathroom. I am planning to have dmx on concrete floor then 5/8 osb on top dmx underlayment to make the subfloor. Here I have 2 questions:
1. Do I need to use self-leveller on concrete first or over the OSB?
2. Can I just put the tiles over osb not using the This Ditra?
Any suggestions will be appreciated.

Can you use Schluter®-DITRA over a hydronic floor system that includes 1/2" wood system, (Viega) with pex tubing grooves?

Hi mate. Awesome video. If I have wooden floorboards, do I need to apply 5mm ply Screwed down before putting the Ditra matting?

Thanks for the video. Your coverage was not great when you peeled back to show. You should get much better coverage if you mix just a tad thinner and don't put too much pressure on the trowel!

I find it funny that I just came from HD to purchase this. They didn't carry it.
Nor did they carry modified thinset or the additives to make regular mortar more flexible.
HD get your crap together.

to move knee over sement ( actually into mortal ) is very unprofessional man.. and try to not move notch so frequently

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