When using Kerdi for your shower floor you need to make a hole in it for the drain. If you don’t then you simply have a shallow swimming pool rather than a shower. This hole must be the exact size and it must be in the correct spot. There are two ways to do this.

The first way is to install your membrane on the floor then cut out your hole for the drain. While this method works, I’m not a fan. It leaves open the possibility of cutting more than just your membrane (where it needs to be cut), slipping and damaging the drain or messing up the bond of the membrane around the drain where you need it to be bonded (accidentally debonding a portion of the membrane while you’re cutting the hole).

It works, but there’s a better way. I’m assuming here that you’ve already cut your hole in the floor, installed the drain and mud deck and cut your kerdi membrane to the correct size for your floor – the width of your floor plus four inches, by the length of your floor plus four inches. That is your floor size plus two inches up each wall. Got that? Good, let’s move on.

In your Kerdi drain box there are two templates. One is for the hole in your subfloor, so the drain fits down into it correctly (it says cut-out template for floor), and one for the membrane (it says cut-out template for kerdi membrane). Grab the one for the kerdi membrane – I’m assuming you already have the hole cut out in the floor, yes? If not you’re doing it wrong… Remove the inner circle – this is the part you’ll be using.

Set the template (the circle) into the center of your drain. It will fit perfectly into the center depression of the Kerdi drain. Measure your shower floor in each direction to the center of the template, the little cross, plus two inches. For instance: if your shower is 36″ deep x 48″ wide and your drain is centered then distance to the cross should be 20″ from the back (18″ plus 2″) and 26″ to the side (24″ plus 2″). Write those numbers on your template in the appropriate spots – 20″ at the top of the cross (to the back wall) and 26″ on the side of the cross (to the side wall).

You can click on any of these photos to see a full-size version.

Marking the center of your drain

Marking the center of your drain

Now take your Kerdi membrane and lay it out in the same orientation in which it will be in the shower. Measure 20″ from what will be the back of the shower and make a mark, then measure 26″ from what will be the side and make another mark. You should have a cross on your membrane similar to the one on the template. That is the center of your drain in the shower.

Now take your pen and place the tip right in the center of the cross. Gently push the tip of your pen through the template so it pokes out the back of the template like this:


pen tip placementPush pen tip through to the other side

Once you’ve done that fold the template back so you can see the pen tip and place it directly onto the little cross you made in the membrane. Then hold it firmly in place so it doesn’t move and remove the pen (Do this with the other hand also unless you’re taking pictures too).

centering the template on the membraneRemove pen from template

Tracing the template onto the membraneNow just trace around the outside of the template onto your membrane.





Cutout markings on kerdi membraneOnce you’re done with this you should have a perfect circle on your membrane in the exact spot as your drain in your shower.




Cutting out the drain circle

Now take your razor knife, scissors, bowie knife, whatever, and cut the circle out of your membrane – take your time! It needs to be exact and there are no second chances if you slip.




Completed drain cut outThat’s it. Now you have your drain cut out of your kerdi membrane in the correct location.




Now you can lay it into your shower floor and everything will line up correctly without any problems. I normally roll it up from each end to the center so when I lay it into the shower floor I place the cutout directly over the drain and roll the membrane out from the drain in each direction. That way you ensure it’s in the correct spot.

Completed shower floor with Kerdi membrane

Although this sounds like an extremely long process because there are a lot of words on this page, it’s actually quick and straight-forward. If you use this method you eliminate the possibility of damaging your membrane and you end up with a hole where you need it and the size you need it.

Oh, and if you actually cut it out with a bowie knife – send a picture. I gotta see that! :D

{ 65 comments… add one }

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  • Jodi Mccoy

    Here’s a question that will make you wonder if I should be installing this myself. I laid the membrane on the shower floor (the pre formed tray), cut the hole for the drain perfectly, took the membrane out, put the mortar down, then laid the membrane. I didn’t realize until I had embedded it that the hole is slightly off center. It is still only on the white part of the drain, but not exact, like you describe. How big of a problem is this, and is there any way to fix it? Thank you!

    • Roger

      Hi Jodi,

      No way to fix it short of replacing it. But it isn’t a big deal at all. You should be fine.

  • Bill

    Hello Floor Elf,

    I am building a walk-in shower with the Schluter shower system but I’m getting different opinions on the tiling.
    1. Is it better to tile the walls first or do the floor first?
    2. Which would be your preferred sequence if you were using inside corner profiles?
    Thank you for your informative (and entertaining) site.

    • Roger

      Hi Bill,

      Over properly waterproofed substrates it honestly doesn’t matter which you do first. I always do my floors first, I just think it looks better with the wall tile over the floor tile.

  • David

    Hi Floorelf,
    I doing a shower area and want to use a linear drain.
    On the joists I made a wedge of 3/4″ to zero over a 3′ length to create the slope, I then added 2-layers of 3/4 plywood for the floor.
    My question is, can I now use kerdi on top of the plywood floor or would ditra be better prior to tiling.
    I would also use kerdi on the walls

    Would I need to add some other waterproofing on the plywood before the schuleter products?

    • Roger

      Hi David,

      Ditra for a proper substrate with kerdi over it for waterproofing.

      • David

        So your logic being that the ditra adheres to the plywood and the kerdi adheres to the ditra, is that the reasoning?
        If so, could I then use Hardi board then kerdi, would that achieve the same goal?

        Also just spoke to the guy that’s installing my tiles, he said he’s seen lots of times the kerdi on top of plywood then tiles.
        He did say it’s not Schulter approved but never had any problems in 10-years

        So now, I’m confused, thanks in advance for any more help

        • Roger

          Yes, you can use hardi with kerdi over it – same result. Do you want to be the ‘first’ problem he’s had in ten years? :)

  • Evan

    Im installing a shower which is 36×60 with an offset drain. Well the homeowner orders a 48×48 kit. Ive had to cut so much pan off of my long side, that when it meets up to the factory side, it leaves a nasty angle cut with the tile. Now the homeowner is complaining about the tiles not being the same size cut at the bottom of the shower. Is there any way to fix a pan that is already premade? Any tricks to stop this from happening on other jobs besides the obvious patch?

    • Roger

      Hi Evan,

      You should not have installed that. If they want to order materials they need to order the right stuff, if not, it doesn’t get installed. Your best bet is to install them the best you can then pack a 3/4″ layer of deck mud in it and form it so everything is even. Or just make a dry pack pan.

  • Dick

    Dearest Elf,

    I have a dilemma. But first let me exclaim that I read through your on-line book and have already benefited (the part about modified and unmodified thin set was very helpful.) Here goes and if you have too much heartburn helping with what I am about to describe I totally understand. To begin with I fall into the category of owning nearly every tool you can describe (including portable sawmill) but do not consider myself an expert in any of them (i.e. there is always room to learn.) I live in a home in Colorado built in 1999. It was a custom built home with presumably knowledgeable subcontractors but a notoriously cheap GC. I am preparing to sell the home and know the shower pan in the master has a problem. I am remodeling the bathroom, but trying to keep budget and schedule at a minimum. I did a flood test and discovered I do indeed have a leak. At the advice of a tile professional (and friend) we agreed the shower pan would need to be ripped out and redone. As I carefully removed the floor tile (installed over the top of another floor of tile) and one course of wall tile I quickly discovered the root cause of my problem. How can the shower pan liner leak when there is no shower pan liner? Yep and the walls appear not to be waterproofed either. Makes me lose my sense of trust. I recognize the only way to fix this problem 100 percent is to rip out all the tile and start from scratch, but unfortunately that’s not going to happen. My thought is to build a pan liner up the wall 9″ and use Kerdi membrane to create a floor liner. Behind the wall tile is cement board and the wall to wall transition will need waterproofing as best as I can do. The existing floor is well sloped with tile on a mud pan that is very stable. My thought is to go over the top of the floor tile with Kerdi membrane and use an extender for my drain…until I read the part about the Kerdi membrane needs a kerdi drain. Does Kerdi make an extender for a “remodel” such as this. If not do I need to bust out the old drain and replace it with a Kerdi drain? Very much appreciate your help…and any sympathy you might have.


    p.s. I hope Santa brings you all the power tools you dream of.

    • Roger

      Hi Dick,

      They do not make an extender, the closest thing they make is a conversion kit which is essentially the kerdi drain that bolts onto the lower flange in the same manner as the upper flange would bolt onto it. You can use one of those and use the ‘divot’ method (just google it). Using that method should get you a passable shower that drains correctly and doesn’t screw up everything around it.

  • J

    After installing the kerdi shower kit and completing the tiling. I have noticed around the drain, where the flange would be, there is bounce when you step on the tiles. The tiles are not breaking but the grout is cracking. How do I fix this?

    • Roger

      Hi J,

      The first thing you need to do is figure out why it’s bouncing – it obviously should not be. Did you get complete coverage of thinset both beneath the pan as well as under the drain flange?

  • Ed

    Hi Roger,

    Your books and website have been a tremendous help to me learning better ways and tricks to tile installation. Thanks!
    My whole shower is covered with kerdi membrane walls, ceiling ,floor and as i am going to use pebble tiles for floor i have tiled everything but the floor first.
    Where wall tile meets kerdi membrane floor should i seal that with silicone or kerdi fix before i install pebble tile?

    • Roger

      Hi Ed,

      Provided your shower is properly waterproofed you don’t want to seal the wall tile to the membrane with anything.

  • Dan McDermott

    1st question: With a Kerdi shower, how complex/difficult is it to replace the drain in the future if it develops a leak? Do you have to rip out the entire floor?

    2nd question: My shower will be a neo-angle which I have heard are notorious for leaks. On a Kerdi showqer, how hard is it to fix such leaks (if they ever occur)….around the show glass door where it meets the wall and especially where it meets the shower floor in the corners?

    • Roger

      Hi Dan,

      1. Yes, at least around the perimeter of the drain – just like you would if a regular drain failed ‘sometime in the future’. :D

      2. If it’s built and waterproofed properly it will never leak.

      Stop planning a shower based on how difficult it will be to repair if it fails. Build it correctly and it will not fail. :D

  • Art

    Roger, thanks for all the great advice. Just a quick comment on cutting the drain hole. I laid the Kerdi membrane in the shower and got it exactly where I wanted it then placed the cut templet ( the square part with the hole in it) on the drain. I could feel the edge of the drain so when it was lined up perfectly I taped it down with blue tape. I picked up the floor and cut around the inside of the templet with a razor knife. Perfect hole in the perfect place.

  • John


    Why add the extra 2″? If the drain is perfectly centered, shouldnt the center just be whatever the width is divided by 2, and whatever the height is divided by 2? Thanks!

    • Roger

      Hi John,

      Because you need to run the kerdi 2″ up each wall around the perimeter. Your sheet of kerdi should be a minimum of 4″ longer and wider than your shower floor.

  • Kevin

    I have installed the Kerdi membrane over the preformed kerdi shower bed. While installing mosaic tile. One of the small tiles was cracked. While removing this tile I had to cut the mesh backing. In my haste and not thinking i cut the mesh and may have cut into the membrane. Impossible to tell. If there was a hole in the floor membrane. And it was properly bonded to the pan. Would it leak? It seams that with the way the membrane is cut for the drain it is not much different than a elsewhere on the floor pan. Or am I just trying to give myself false hope? The tiles are set and not grouted. Could I test using a drain plug and doing a flood test?

    • Roger

      Hi Kevin,

      It may leak, do you really want to take that chance? Yes, you can flood test it, but it would be better to attempt to seal that slice (if there is one) with some kerdi-fix before bonding the new tile. Unless you’ve already replaced it, in which case a flood test is definitely in order.

  • Tony

    Hi Roger,

    My shower has an angle step so its not square, question for you

    I’m using 36″ roll of Kerdi membrane and not all the sides meet the wall should I install the membrane on the wall first and then have the floor membrane go overtop or should I cut out 4-6″ strips and have the strips overlap both the floor and wall membrane if you have a picture that would be great.
    I have pictures which I will send to you not sure how to attached them thru this chat board.

    The subject will read – Drain cutout for your Kerdi membrane

    sent to your email address :whistle:


    Tony Mazz

    • Roger

      Hi Tony,

      I would place strips there first to accommodate the 2″ overlap on both the wall and floor, then install the floor membrane.

      Posting in several places (FB) does not get a faster answer – day job and all. :D

  • LT

    First timer here. Maybe one of the dumber questions you’ll get but here goes. Placed the kerdi membrane over all walls. No problems so far. Used the kerdi shower pan and drain. Here is where I lost my mind for a few minutes. I placed a sheet of the kerdi membrane (with drain hole cut out) over the floor pan before setting the drain! Then to compound the problem, i then set the drain on top of the kerdi membrane with the thin set. Then I realized I had goofed. Please tell me all is not lost. Could I place another sheet of the membrane over this and just basically have a double layer of kerdi? Needless to say, this was my first attempt at this and after a long 10 hours of walls and corners my mind was numb.


    • Roger

      Hi LT,

      Yes, you can put another layer of kerdi over it. Do you do everything the hard way? :D

  • Rebecca Watson

    Why does a round drain have to be in the middle of the shower stall? Can’t it be in the back left or right corner, where all the water pools anyway?


    • Roger

      Hi Rebecca,

      Really? I’m going to assume you’re being serious, so I have two points:

      1. The drain can be anywhere in the shower.
      2. If water is pooling in a corner it has nothing to do with your drain and everything to do with your shower floor being improperly constructed. If your drain is not the lowest point in your shower floor then the person who built it did it incorrectly.

  • joseph gutierrez

    i need to know if i can put ditra on wood shower subfloor then put kerdi membrane on top of it then tile over,,,thanks

    • Roger

      Hi Joseph,

      Not as your shower floor. You can put ditra, then a mud slope, then kerdi membrane, then tile. (I assume that’s what you meant, but the one time I don’t specify it…you know…)

  • Roland


    I think I have an issue. I’m installing a Kerdi shower pan and drain on concrete slab for my shower remodel. I had to demo around the existing drain pipe (pvc) in order to cut it down to the right height and to install the 4″ coupler. I was able to cut through the concrete and get to the sand/stone below it (about 2″) and installed the coupler and cut the drain. Covered it with concrete and went well. Then I poured leveler over the entire area to get a leveled concrete floor. Went to dry fit the drain and found that I did not install the coupler so that the pipe was right in the center. Now the drain does not set all the way down cause it is hitting the coupler on one side. I’m off by about 3/16″ to 1/4″ off center. Will I have to tear it up around the drain again and adjust it? Really don’t want to pull out the rotary hammer drill again if I don’t have to.

    Thanks again.


    • Roger

      Hi Roland,

      You can cut the pan to get the drain to fit, and fill in any open area opposite the cut that it no longer covers with deck mud, then install your kerdi over it.

  • Thomas


    Fantastic site. when I dig I usually find the answer to my question except this one. I mudded in a kerdi drain using a cleavage membrane and metal lath, however I only did so underneath the drain to set it with the deck mud coming out to the outside edge of the kerdi drain. It has long cured and now I am ready to complete the sloped deck mud job. I am pretty sure the new deck mud will not bond completely to the old deck mud. Is there something I can do to help make a good bond.

    • Roger

      It will bond. If you want to you can put thinset on the cured mud to get a better bond.

  • Pat

    I too find you sight very informative and insightful. That said, I do need your assistance. I have been working on a second story bathroom and removed tub and installed a Schluter System shower unit. I just tiled the shower floor and think that the Laticrete 317 I used was old because the tiles did not set very well. Unhappy with this, I removed the tiles and scraped out as much of the thin set as I could and wiped it down. My question is this: Can I now just reapply new thin set and set tiles or should I re-Kerdi ( new word) the shower floor?
    I would like your opinion on another item. In this on going project, I removed all bathroom floor tile and am laying out the 1/4 in Hardiebacker. The subfloor is plywood and even after calling James Hardie and them confirming that sealing the plywood is not necessary prior to applying thin set, I am a little uncomfortable just doing nothing. What do you think?
    Keep up the good work and thanks.


    • Roger

      Hi Pat,

      Provided you did not damage the kerdi at all you can just go right over it.

      You don’t need any type of sealer over the plywood if you use modified thinset.

      Sorry for the delayed response, my spam filter went ape shit last week for some reason, I just found your comment in the spam folder, I hope the answer found you in time.

  • RBO

    Oh, boy. I just realized that I can’t use the PVC membrane with the Kerdi drain I installed yesterday (glued into the drain pipe with no access below). My slope from wall to drain is fine but because I thought I would have another layer of deck mud on top of the membrane my pre slope is a bit rough. Can I skim coat anything over the pre slope to fill some low, flatish, areas and make it smooth enough to thin set the Kurdi membrane into it?!? It seems to me that the thinset really has to be thin between the mud floor and the Kurdi membrane.

    Thanks, you really are the best!

    • Roger

      Hi RBO,

      You can skim-coat over it with thinset to get it flat, let that cure, then install your kerdi.

      • RBO


      • john

        hey roger, on this particular question. i have kinda the same issue, i need to do a skim coat on my mud bed before i put the kerdi down. shoulk i use an modified are unmodified thinset to skim with. i know i have to use unmodified to install membrane

        • Roger

          Hi John,

          You should use a modified. And I assume you’re going over concrete, no? Because if it’s over wood you need modified to put down the ditra.

  • jeff

    Ok, so this question is kind of coming from left field, but that’s generally where I live. After having tile from our 10 year old shower pull off the wall attached to suction cupped stabilizing bar as I was standing up in the shower, only to find the wall it had been attached to was an enormous pile of molded drywall and soaking wet insulation (no vapor barrier inside the shower, everywhere else in the house, but not the shower) My wife decided we would remodel the bathroom with a larger shower and use Kerdi membraine and Ditra to completely waterproof the bathroom. So after purchasing the materials, and planning everthing out, she discovered that the cost of a two sided glass enclosure 36 x 48 with a shortened side resting on a whirlpool bath, was somewhere in the ballpark of $2500. Adding in the cost and labor required to install shower hardware, body jets, shelf-like shower niches, etc., she decided to take a second look at a prefab jumbo whirlpool-steamshower-media ready-aquatic- nervana which
    was previously passed up at $3500. Needless to say we currently have said “bathing excess” sitting in our bedroom waiting to be deployed. However, I have run across a small hitch in her plan to use Ditra and just tile the entire floor then install the shower/tub on the tiled floor, and that is the drain. She initially planned to just put a Kerdi drain in the floor attaching it directly to the plywood sub floor and then insert the discharge hose into said drain, and poof we’re done, the floor would be waterproofed, and any accidental over spray from the shower could be simple dried off the tile or pushed into the drain. As I now have all of the Ditra installed, the Kerdi membrane covering the walls, and the whole room a waterproof sanctuary, I see in the Kerdi drain installation directions that it suggests a minimum of 1″ of mortar beneath the ridge of the Kerdi drain when installing it over Plywood subfloor. Given that I am not putting the drain into a shower floor, I would really prefer not to have to pull up all the Ditra and cover my whole bathroom floor in an 1″ of mortar, can I use the Drain without fear of tile cracking or it undermining the whole uncoupling system created by the Ditra? Or am I just screwed?

    • Roger

      Hi Jeff,

      Put thinset beneath your drain when you install it in the floor and it should be just fine.

  • Steve


    I am doing a kerdi shower using a deck mud pan based on your e-book. I did the pan tonight and I have a few questions.

    1. I was so afraid of making the mix too wet that I’m afraid I may have used too little water. It was cohesive enough to hold a shape when formed with my hand, and it was wet/moist to the touch….but with one batch in particular I noticed some clumps that didn’t seem as wet as the rest. And in some cases small dry specks of mix. Not much at all by volume, but it concerned me that maybe the overall mix was on the dry side. I just mixed it in the pan a bit, distributed it around with some of the other (slightly wetter) batches, and kept pounding away at it. It seemed OK to me, but I don’t know what the hell I’m doing. Should I be concerned? Rip it out and do over?

    2. I followed your directions for setting the drain, but I got a bit confused. (BTW: I set the drain after I had packed in the deck mud for far half of the shower, not at the beginning) My understanding was that I am supposed to put the drain in the styrofoam holders and pack the mud in under the drain while it is in place. It never made sense to me, but that’s how it reads to me. I tried that for a while, but gave up. What I ended up doing is a “step and repeat” sequence of: set the drain in place, gauge where mud is needed, remove the drain, pack the mud, re-set the drain and check. After about 10-15 iterations I had a drain that was supported by a ring of deck mud…It “felt right” to me, but it seemed to be different than the directions. Am I OK here, or did I mess something up by removing the drain like that?


    P.S. my hat is off to you and tile setters everywhere — this is physically demanding work.

    • Roger

      Hi Steve,

      Your deck mud is fine, it just didn’t get mixed thoroughly. As long as you mixed those spots up with the rest as you were installing it you’re just fine. The drain is also fine. My method is just the method schluter uses, it gauges the height of the drain off the substrate. As long as you have it fully supported it’s fine.

      • Steve-o

        Thanks, Roger. To clarify, I did still use the styrofoam spacers to index to the subfloor, taking them out one by one as described, but I just couldn’t figure out how to pack mud under the drain. I could get it underneath the drain, but wasn’t sure how to pack it without it falling into the hole in the floor. I wanted to, you know, “beat it like a DMV employee”; all I could come up with is beating on the face of the drain (seemed like a bad idea) or removing the drain so I could go to it with a 2×4 and hammer. At this point it doesn’t really matter for me (though I am curious), but you might consider adding some detail on this in the book for us slow ones… ;)

        1. I went with your method for setting the drain (doing it the next day) – you describe removing the drain as a slow process where you have to gently wiggle it free. Mine lifted right out without any effort to speak of. It seems totally fine otherwise, but I’m wondering what I may have done wrong, or if it’s OK like that.

        Pictures are here if you care to look:


        2. I noticed the white bonding surface of the drain got a little bit scuffed up during the install. There are actually a few places where sand abraded small holes in the white material so that the ABS shows through. Additionally when I went to clean off the deck mud goobers, I noticed the white stuff acted like paper when I got it wet and started to disintegrate. I stopped right away, but I’m concerned that the mating surface might be compromised. Am I OK here, or do I need to address it somehow?

        • Roger

          I normally drill my hole in the floor so when the drain is placed into it there is no space between the drain and the subfloor for mud to fall into. Yours is just fine. Sometimes it lifts out, sometimes you need to wiggle it a lot. Depends on how the mud cures. Again, you’re fine.

          The fleece on your drain is fine as well. It’s there to enable bonding of the kerdi to the drain, everything under the fleece is waterproof. It’s fine.

          • Steve

            Thinset shrinkage/cracking at kerdi drain triangles…


            I used Versabond, and mixed according to the directions. Not watery. Thick pancake batter? It held a 1/4 square notch fine. I estimate the thickness of the thinset layer at about 3/16″ average, though some low spots could be 1/4″ or so.

            You can see in the picture that the triangle area is dimpled down and cracked. Is this a problem or an indication that I did something wrong? The drain feels well supported.

            Assuming the drain is fine as it is, would shrinkage and cracking like this be a problem when I install the tile? Suggestions for preventing it?

            • Roger

              Hi Steve,

              It’s no problem at all. The reason it cracked is because you’ll have almost a full 1/4″ of thinset inside those triangles. That thickness with versabond will cause it to shrink.

  • Jan

    Roger, Can I use the Kerdi drain without using the whole kerdi system in my shower? Or does it only work with their system…
    Thank you!

    • Roger

      Hi Jan,

      It only works with topical waterproofing membranes like kerdi (of course), redgard, hydroban, etc. You can not use it with a regular pvc or cpe membrane.

  • Mike Nickau

    hi Rodger, how’s it going? so far I have found the answers to my questions by going through the site, but “of course” I still have questions…Okay, here I go…Will kerdi board be strong enough to support the weight of the tile if used on the ceiling? how do I handle the flaps of the kerdi membrane in the corners after I apply it to the shower pan? and last but least, I want to put a small glass block window in the wall of the shower; is it best to tile the opening completely before building the window, or build the window on top of the kerdi board and tile up to it? oh I’m sorry, I did not mention that I will be using 1/2″ kerdi board over 2×4 wood frame and I would like the use the Pittsburg glass block with the track. make sense? anyway, I hope all is well and I look forward to your response. mike.

    • Roger

      Hi Mike,

      Schluter wants 5/8″ kerdi-board for ceilings. I have done it with 1/2″ and doubling the joists, but that’s what they want. Yes, it is plenty strong enough. You use the corner pieces included in the drain kit for pan corners, they are one-piece ‘cones’ that fit right into a 90 degree corner over or under the membrane to seal them. Build the window on the kerdi-board and tile up to it. Attach your track to the kerdi-board (screwed through it to the 2×4, then tile up to the track.

      • Mike Nickau

        Okay brother you got it…Thanks so much. Hopefully I’ll be able to send a few photos before Christmas…Ahhhhh…….Mike

  • Bill

    I am getting ready the install a kerdi shower using the mud bed method for the floor. When I looked at the drain assembly, I am not sure what holds up the actual grate. Do I put enough thinset under it to bed it in?


    • Roger

      Hey Bill,

      The grate pops into the large cylindrical tub, the ring goes around it under the grate. When installing the ring with the holes is pressed down into the thinset until it squishes out of the holes, then the thinset is flattened down over the ring. The tube supports the grate and the ring holds it in place. Essentially yes, it is just thinset. But the manner in which the parts go together keep it where it is placed.

  • Hemy

    Hey floor elf,
    Thanks for the article another big help! question though, I notice in your picture you have two sheets of kerdi on the floor as one sheet is not big enough to cover the area of the shower floor. Sooooo, Qustions: 1)Do you take any precautions other than those mentioned by Schluter when bonding the two membranes together? being that it is on the floor of a shower there would seem a higher probability of leakage as
    opposed to being on the wall…do you overlap the outside sheet over the inside sheet (or the sheet further from the drain overtop the one nearer to the drain) being that the floor slopes drainward. 2) Or is it simply appropriate to do as Schluter recommends when bomding kerdi together and over lap sheets bonding them together with the proper thinset? 3) Oh and as well, what size notched trowel do you prefer when adhering kerdi to shower walls and floors?

    Thanks Floor elf your the greatest!!

    and hey if you cant think of your next piece to write, may I suggest an article on the how to’s of installing square tile on the diagonal. Tricky for a fella Like me, Sure it s a walk in the park for an Elf such as yourself. Haahah Thanks again!!

    • Roger

      Hi Hemy,

      That shower has one piece of kerdi – not two. I don’t know if you’re seeing the curb at the bottom as a second piece, or the slightly darker stripe on the left of the drain – that’s where the end of the roll overlapped, but it is only one piece. A two-inch overlap is plenty sufficient when seaming floor pieces together, never had any problems with that and I flood tested every one. Yes, I do overlap the sheet further from the drain over the one closer. You don’t HAVE to, but I sleep better at night – it would bug the piss out of my OCD if I didn’t do it that way. I use a 1/4″ x 1/4″, but it’s worn down a bit so it’s more like a 3/16″ x 1/4″.

      I will put that post on the list! Thanks.