During demolition of the old master bathroom, we discovered that our floor joists were spaced wider than we originally thought. And under the old tile was a thick mortar bed. A finding we had NOT expected. Enter Schluter systems and this awesome tile underlayment product, the Schluter Ditra XL.
*Thank you to Schluter Systems who provided us with free product in exchange for our review and this content. And I’d like to thank them especially for making this product such a lovely color. I craved orange sherbet and creamsicles for two days straight. You guys are the best. This post contains affiliate links. Please read our full disclosure policy here.*
Today, we’re sharing with you what we’ve learned about subfloors, tile installation projects, underlayment, decoupling products, and why we chose to use the Schluter Ditra XL. If you’re contemplating a bathroom renovation, or DIY tile installation project, this information may come in very handy to you…
If you want some quick and dirty info about this Schluter Ditra XL underlayment product, start here with the video overview:
Why we chose Schluter Ditra XL for our bathroom tile installation project:
During demolition of our master bathroom project, we hit our first “snag” of the renovation process. When we started removing the old 12×12 stone tile (seen below), instead of hitting a plywood subfloor below, there was a 1” lightweight concrete subfloor with embedded wire mesh.
We hadn’t ever seen this type of subfloor in any of our other renovations, but I knew there had to be some explanation for why the original floor would have been installed like this. No chance someone just decided to go through what would have been a much more labor intensive process for no reason. And I knew I needed to understand that “why” so that I didn’t make some sort of mistake as far as working with a proper subfloor went when we were ready to install the new flooring.
I turned to Google, YouTube…the standard fare, and began to find a ton of information regarding the proper sub-flooring types for different tile installations. Scouring through all this information emphasized the importance of getting this subfloor situation right! Without a well-laid and appropriate subfloor, any new tile we laid could crack down the road.
After some digging, I figure out that “why”. Being on the 2nd story of our house, the structure of the our floors is ¾” plywood floor and we have wood joists spaced at 24” on center. That 24″ number is the key. The larger the joist spacing, the more “flex” your floor has structurally. 24″ spaced joists meant that my floor could have a decent amount of movement in it.
24” joist spacing in residential construction is about the max you will see. It’s not atypical to see this type of spacing, but the potential issue we were facing is…
floor movement + porcelain tile = cracked porcelain tile (uh-oh)
I needed a way to “decouple” the floor movement from the porcelain tile to ensure that my new tile floor would not crack. The contractors who laid our original bathroom tile accomplished this decoupling by installing that 1” concrete subfloor over top of the plywood. The concrete layer created a decoupling membrane to allow the floor to flex without cracking the tile.
The thought of recreating this subfloor was NOT something I was excited about AT ALL. It would take a lot of bags of concrete to create a 1” over my entire bathroom. Just the thought of hauling bags of concrete up the stairs was enough to make my back hurt. And trying to make the entire concrete floor level?? For someone like me, Harry Homeowner, that sounded next to impossible. There had to be a better way…surely someone had come up with a better solution.
Back to Google I go. And in less than a minute of searching, up pops Schluter Systems. They manufacture a whole array of installation systems for tile and stone.
As I scanned their products, I became more and more interested, and I also kept thinking I had heard of them before somehow. And then it dawned on me. Full disclosure…I have a man crush on Mike Holmes, you know, the Canadian contractor who had a show “Holmes on Homes” on the DIY network…anyway, he swears by the Schluter products, and that’s where I’d first heard of them years back. I just had not realized they made the exact product I needed and it was going to make my life (or at least this project 😉) much, MUCH easier.
The product I needed is called the Schluter Ditra XL. It is a lightweight uncoupling membrane that will prevent tile and grout from cracking as the floor below moves and flexes. The “XL” product is specifically made for floors that have a joist spacing of 24”…bingo.
The Schluter Ditra XL was EXACTLY what I needed. I downloaded the installation guide from the Schluter website (which you can do even prior to purchasing) and dug into the info there a bit deeper. They have excellent examples of different subfloors and how to properly install their product. I read through this and sure enough this confirmed that this product would work great for my project.
A few weeks later (OK, a few months later) once we had the old bathroom demolished, plumbing rerouted, electrical run, drywall complete and the shower pan installed, it was finally time to start tiling the floor.
I reviewed the installation instructions on last time, and I even call Schluter to confirm how I was to properly install this. My wife is rolling her eyes right about now, but hey, it is better to take your time and make sure you know how to install it correctly then to rip it all out and start over (I’m pretty sure Mike Holmes would be proud…and on my side, not my wife’s on this point).
The Schluter tile underlayment mat is very easy to install. The materials you will need are based on your application, but the only items we needed for our specific job were:
- Schluter DITRA XL underlayment
- unmodified thinset mortar (*clarification: modified thin-set mortar over wood subfloors; Schluter SET, ALL-SET, FAST-SET, or unmodified thin-set mortar to install tile on top of DITRA-XL)
- ¼”x ¼“ square-notch trowel
- sponge/bucket of water
- box cutter
- grout float
**Specific items needed will vary based on your specific project and application! See the Schluter website and installation guides for more information**
Schluter Ditra XL installation tips:
**This is NOT a full installation tutorial for this Schluter underlayment product. The best source of information for installing this product can be gleaned directly from Schluter’s website where their installation guides are free and downloadable.**
Time to install the mat…I grabbed the Schluter Ditra XL and carried it upstairs (this was much easier than carrying up the 20 or so bags of concrete it would have taken for the other option!) The 175 sq ft roll of Schluter pad we had weighed about 10 pounds. My back is still thanking me.
We vacuumed the plywood subfloor to get it clean and as free of dust as possible. After vacuuming, we quickly wiped the plywood floor down with a wet sponge to get any final remnants of dust up as well as add a little moisture to the plywood to help keep it from sucking all the water out of mortar too quickly.
The mat can be rolled out and cut to the size needed for your project with a utility knife. Super easy.
It helped us to have a couple sections pre-cut so that you can roll through the installation a bit quicker once you get your thinset mixed.
Simply dry-fit in the area you’re going to install, and cut sections to length (and width if needed) with your utility knife.
We learned as we went that using the MAX amount of water recommended by the thinset manufacturer worked best for installing this Schluter Ditra XL mat. Having the thinset wetter made it much simpler to spread out a nice, even layer. To spread the thinset, we used the ¼” square notch trowel (listed under supplies above) and then rolled the Schluter Ditra XL mat out (white side down!) over the thinset.
Making sure the Schluter Ditra XL mat is thoroughly embedded in the mortar is a must. We used a grout float to help us push the mat down into the thinset firmly and evenly. You can walk on the mat immediately after it is laid out, so when using the grout float get right on the mat and use your weight to push the mat into the thinset.
Once you think you are done, pull back a corner of the mat and make sure you have full coverage, if not, get back on there and work it some more. In the image below, you can see there are still a couple of areas where the thinset looks either very thin, or like it hasn’t penetrated that area yet. In this case, we put the mat back down, and continued to apply pressure until the entire pad was covered with thinset.
Keep going this way until you have the entire floor covered. For our bathroom, which is approximately 170 sq ft, it took us about 2 hours total to complete the Schluter Ditra XL installation process.
We finished laying our 12×24 tile over the Schluter Ditra XL about a month ago now, and it looks great! No cracked tile so the Schluter Ditra XL appears to be doing its job wonderfully. Good luck with your tile floor! And if you have questions about either our experience, or the Schluter Ditra XL product, feel free to leave us a comment, or call the good folks over at Schluter. We did (several times) and they were very patient and helpful to us.
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