How to Install Uncoupling Membrane

If you are laying tile on a concrete slab, you will want to use a uncoupling membrane. Don’t worry, these are available at your big box stores! If you’re not convinced you need it, Schluter has studies showing why you want it, but the gist of it is nobody likes cracked tile and an ounce of prevention is worth a pound of cure.

Rating:

Decode with the handy-dandy guide here):

• Time  this project will take an afternoon
• Money this project will cost less than $500
• Tools   this project requires speciality tools (but they’re ~$20 each)
• Experience   I’ve used these tools before but never this particular project
• Strength  if you can carry a case of water from the car to your house you’ll be fine
• Risk  if you mess this up it will make tiling and grouting harder
• Suckage   this project is sweaty and messy but saves you moolah

Tools:

• GOOD knee pads – if you’re doing a small area, like a closet, cheap knee pads are okay, but anything larger and your knees will be killing you if you cheap out
• 1/4″ v 3/16″ V-notched Trowel, 5/16″ x 5/16″ V-notched trowel, or the DITRA 11/64″x11/64″ square-notched trowel
• Margin trowel (for tight spaces and as your “scoop” for the thinset)
• 10A Drill (corded will be cheaper, a smaller drill will not appreciate mixing thinset)
• Paddle bit for thinset (found in the tile section at the store)
• At least (2) buckets (one for thinset, one for water. These will be destroyed, so don’t use any you want to reuse later)
• Sponges (I used new kitchen sponges and “tiling sponges”, both worked fine)
• Box cutter
• Grout Float (to smooth out the membrane)

Materials:

• Schluter Systems Ditra 54-sq ft Membrane
• (1) 50 lb bag of uncoupling membrane thinset per 150 sq ft
• Water supply that can fill a 5 gallon bucket

Step 1: Prep the Floor

Step 1 is covered here. Be sure to check out the series to find out all you need to know about installing tile on concrete.

Step 2: Plan Your Room

One thing that is nice about this uncoupling membrane is you can walk on the uncoupling membrane as soon as it is installed. However, I still like to start in the far corner of the room and work my way towards the door. It’s good practice for when it is time to lay the tile (which you absolutely do NOT want to walk on as soon as you lay it!). If you are intending this membrane be waterproof, you will want to minimize the number of seams, because at each seam you will need the special tape to join the pieces together if you need it waterproof. I didn’t care about this, so I patchworked it across the room.

Step 3: Mix the Thinset

For your first attempt at thinset, mix a small batch to get the hang of using a trowel. Add approximately 3 inches of powered thinset to one of your empty buckets. Make sure you wear a face mask because this stuff hurts to breathe. Slowly add a little water. Mix with the paddle on your drill. Add a little more water, then mix. Continue until your thinset is the right consistency.

Mix it a little runnier than you would thinset to install the tiles themselves. The best way I can describe this is to the texture of creamy peanut butter. A way to check your consistency is to dip your trowel in so there’s a big glob. This glob shouldn’t slide off from gravity alone, but should come off if you gently shake your trowel. Use your margin trowel to scrape the sides and mix in any pockets of powder that are hiding in there (they are not fun to find when you’re in the middle of installing the membrane!).

The instructions for your thinset will tell you to mix for X minutes, then wait Y minutes, and then mix again for Z minutes. Do this! The time you spend waiting is an important part for thinset. It is called “slaking”. You will notice the texture is different when you come back to it after letting it rest for a few minutes.

Step 4: Trowel it Out

Once your thinset is ready, its time to get your thinset in place! Use the margin trowel (the smaller one) to scoop thinset from the bucket. Don’t be shy! Glob it onto the ground a little bit wider than the short side of the membrane. Use your larger trowel to spread the thinset around. Try to have all of the grooves run the same direction, though this is less important for this step. Make sure you use enough thinset. If you don’t you will have to peel the membrane up and apply more.

I’m sorry I don’t have any pictures of this, thinset is messy and I didn’t want to get any on my phone/camera 🙁

Step 5: Install the first section of the membrane

This uncoupling membrane is wide enough to be incredibly awkward to maneuver. I found it easiest to either run the thinset on the entire section I was doing and then carefully rolling the membrane on top, or by cutting the uncoupling membrane into smaller sections and working it a little by little. The cloth-like material goes directly into the bed of thinset, with the orange squares on top.

Press the uncoupling membrane firmly into the bed of thinset. Use the groat float to evenly distribute pressure to the entire face. I found this easiest to use it like an ab-wheel , starting at one corner and working my way over. Fair disclaimer, this step sucks, and its exhausting. Apparently Schluter has a special tool that tamps down the membrane, but I couldn’t find it so I used a groat float.

Now that you’ve carefully seated the uncoupling membrane into the bed of thinset, peel back a corner and see how you did. If you can still see white on the membrane, you don’t have enough thinset. Go ahead an add more, and repeat the awful tedious step until you get full coverage with thinset on the membrane when you peel it back.

Continue your way down until you reach the end of this row. Use your box cutter and cut away the excess membrane. It is surprisingly easy to cut so always cut away from you!

Step 6: Clean Up and Take a Breather

Slow and steady wins the race. I found the best cadence for myself was to use one bucket of thinset, clean up, then take a 10-20 minute break. This kept my back and knees happy, and gave me time to properly clean my tools.

When you are walking away from the unfinished project, make sure you scrape up any thinset that’s not under the membrane. You can flip your trowel up on it’s side and use the flat edge (not the notched side) to scrape it up. Fling this thinset in the garbage (I used a little cardboard box which worked great).

Some thinsets are designed to setup quickly, but the stuff I used started to set up about about an hour. Once the thinset starts to set up, stop using it. Scrape it out of the bucket, and then immediately hose off the trowels, paddle bit, and bucket. Any old thinset will make your next batch start to set up faster so it will have a shorter working time. Use a garden hose with a spray nozzle in a part of your yard you don’t care about getting thinset on. I have a gravel patch that works perfectly!

This next recommendation will sound weird, but stay with me. If you were smart, you used gloves and your hands aren’t dry and achey. If you’re like me, the gloves got filled with water almost immediately, I kept cutting holes in them, and overall they just weren’t practical. However, thinset will suck any and all moisture out of your hands. My hands hurt in a way I couldn’t describe after using thinset, but this hand cream was amazing at making them almost instantly soothed. I have eczema so I have Eucerin already, but you could in theory use any lotion. This stuff just restores moisture very quickly so I could leave it on for 10 minutes, then just wipe my hands off and go back to work.

Step 7: Repeat Until the Room is Finished

Just keep chugging along until the room is done. This membrane can be walked on immediately. According to my boyfriend, it feels like a foot massage so I guess you can enjoy that while you prepare to lay your tile. If you have energy still, you can move directly into laying tile. However, when I did this the first time, I immediately messed up the very first tile I layed, got frustrated, and called it quits. It might be better to let this dry overnight and come to it fresh if you are doing a large space.

If you are ready for the next step, make sure you check out How to Lay Tile

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