How to Install Schluter KERDI-BOARD in a Bathroom Part 2 (Step-by-Step)

How to Install Schluter KERDI-BOARD in a Bathroom Part 2 (Step-by-Step)

All right, so welcome to part two of How to
Install Schluter KERDI-BOARD. In this video we’re going to complete the project and
show you how to make it entirely water-proof. So let’s jump into the tutorial right now.
Okay, so now we got all the wall board up. Now all your seams need to be covered with
the KERDI, and you’re going to thinset that in. What I recommend when you get that KERDI-BAND
is pre-cutting everything to fit rather than trying to fit it in after the thinsetting.
Because one thing is if your utility knife scores any of this, then you’re jeopardizing
the water-proofing. And it could be kind of cumbersome once you’ve got the thinset in
and try to cut this. So I recommend trying to cut all the pieces you need. Now you need
it for all the seams. You need it for around the niche because there’s a seam there as
well. And you’re going to need them for every screw hole that you put in. And for
those, all you need to do is just basically making a little square. So this actual membrane
is 5”. So 5” x 5”, 5” x 4”. Something like that. So cut a bunch of these so that
you can go over every screw hole that you punctured into. So we’re going to pre-make
all those before we mix up the thinset. Okay, so you have to thinset all the KERDI-BAND
over the tub flange, where you’re going to fill in over the KERDI-BOARD and the tub.
And then over every screw hole and all the seams. And what we’re going to use is a
product called Ardex X 77. Now this is a pretty high quality thinset. It’s a non-sag thinset,
not that that matters for the KERDI-BAND. But it is high quality. It’s a fairly expensive
thinset, but I like to use it because when you use it for mosaics, it’s non-sagging.
So say like when you’re doing a 12” x 24” tile and you’re going to do a 3”
mosaic accent in between. This allows that 12” x 24” to sit there and not move. So
you’re not putting all that pressure on that mosaic. So that’s the reason I like
to use it. Just be careful of what you buy. You want to make sure. If it’s not Ardex,
you want to just go with an unmodified if you’re going to go with another type of
brand. So the first mix that we’re going to do
is just going to be a little bit thicker so that we can fill in the tub gap. And then
the rest of it’s going to be fairly loose mix. You want to make it really—I don’t
want to say “soupy” but—something runnier than you would actually set tile in because
you want to be able to get this stuff as flat as possible. So you kind of want to make it
somewhat loose. But for filling that tub deck, we’re going to make it a little bit thicker.
I’m not going to use too much because I don’t need to fill
in that much. So I kind of want to make it
like pancake batter where it’s pretty thick and doesn’t really just fall off the trowel.
That’s kind of the consistency that I want just to fill in that tub deck. And then we’ll
add a little bit water to make this a little bit looser so then we can embed the KERDI
everywhere else. But you don’t want this stuff to sag out of that joint. We don’t
want that. I always like to start with my bottom band
and then do the corners going up the side of the wall. I guess it kind of just makes
sense where that corner wall—where the water hits the wall coming down—kind of flashes
over the bottom stuff, not that it really matters all that much.
I guess I should mention this is actually a KERDI trowel. Basically it’s an 1/8”
x 1/8” notch square notch trowel. But the Schluter brand they do sell the trowels for
their products. So 1/8” isn’t very much. It’s just really enough to embed that membrane.
So I’m just using a drywall knife to smoothen things out. You know I like to use just a
full piece for the whole corners so there’s no gap here in the corner. Make sure you’re
not bulging out of the corner. You want to make sure when you put your trowel in there,
that sits nice and tight. It’s not a bad idea for your first time, just pull this back
and make sure you’re getting good coverage on it. You want to make sure that you can
see that this is actually getting embedded into the thinset. Just re-notched it because
I pulled it back. But it’s not a bad idea just to double-check yourself. And you’ll
see it’s kind of just like drywall tape. You don’t have the seams that pop. But when
you coat with mud it’ll start to lift off. Take a sponge and wipe off your excess thinset.
In our video, Steve shows you how to fill in the gap between the tub and Schluter KERDI-BOARD
using unmodified thinsets. Now Schluter recommends filling in this gap between the tub and the
Schluter KERDI-BOARD using KERDI-FIX. So you would apply KERDI-FIX in that gap. Then you
would apply unmodified thinset on the KERDI-BOARD. And you would fill in that gap using your
KERDI-BAND. So that’s how Schluter recommends doing that instead of what Steve showed you.
Now we showed you Steve’s method because that’s what he prefers. But if you want
your warranty to be upheld by Schluter, you use their method.
The other thing that I wanted to show you is instead of poking a hole into the KERDI-BAND,
you can actually use a pipe seal that Schluter has. So you would slide this over the pipe—this
is a ½” pipe—you would put your unmodified thinset over the KERDI-BOARD, and you would
embed this into that, like so. Now alternatively, what you could do is apply Schluter KERDI-FIX
in this gap here. So you would just fill this in with Schluter KERDI-FIX, and that’s another
alternative way to fill in the gap between the pipe and the KERDI-BOARD.
So basically you trowel the corners like you would apply on mud with the trowel basically
and embed that in the corner. Now don’t overlap that bottom KERDI transition. This
is where it’s just kind of nice. You just fold this in half. It’s kind of nice having
this pre-cut so you’re not messing around with having to cut this in place.
See if you have a little gap like that. It’s not going to be any good. You got to make
sure that that gets filled in. It’s kind of easy doing it in the corner.
So the sponge is really just wiping off that excess to make everything smooth. You want
to make this as flat as possible for when you tile. I guess we have the corner seams
up. Now we’ll do the butt seams. So when you trowel this, have everything go
in the same direction. It’s a little longer, so I’ll have to cut this out. Make sure
you’re not cutting on the board. You need to keep it away. Once you puncture any of
this, it’s not water-proof any longer. So I need to get more in this corner here. So
overlap everything, too, by 2”. So wherever the KERDI is filling over, you want to go
over 2” over. Looks like I didn’t get that corner very well.
Okay then on all your screw holes apply some mud. I like just to putty knife it in. Doesn’t
matter which way you set them. You can set them however you want it. Just make sure those
are embedded. I’m just going to use smaller patches for up here at the top and seal it.
Okay, so now we’re going to do the seam against the drywall and the KERDI. I like
to have my tiles to come out to the side of the tub area just enough so that you don’t
have drywall meeting up against your tub. So 1 ½”, 2”. And if your using a bull
nose tile that’s usually the width that I go outside the tub. So anything that’s
sticking outside of that I usually put a piece of drywall tape. You can pretty much mud over
this, too, on the outside. So this seals around that tub pretty good. Definitely I want to
get the thinset off the drywall area to make it a little bit easier to fit your drywall.
Okay, let’s do the same thing to the other side.
It’s a good idea to cover this corner made with the KERDI just in case any moisture got
behind there. If you just troweled over the corner, and if moisture were to get behind
that tile in any way, it would just rot out that corner pretty quickly. It’s a cheap
steel constructed. So by water-proofing it, it ensures it doesn’t happen.
So I got a
little tear here at the bottom. It’s no big deal. It’s not like I have to get a
new piece. I can just KERDI over it. I got a little rip seam, so I’m just going to
patch it with the KERDI. And that’s what you could do with any instance that you screw
something up or say you got your utility knife in there, you can always just patch it up
with another piece. Now I wanted to show you that here’s our
mixing valve. If you want to completely seal this to make it water-proof, you can put in
a mixing valve seal in the space here. Now Schluter provides this. So what you would
do is place this over your KERDI-BOARD like so and then fill in behind it with the unmodified
thinset. Embed that into the thinset and then you’re good to go. Use a 1/8” x 1/8”
square notch trowel to embed the KERDI-BAND into the KERDI-BAORD. You can also a ¼”
x 3/16” v-notch trowel to do the exact same thing.
So Schulter makes both a ½” pipe seal and a ¾” pipe seal. So whether you’re using
½” or ¾” pipe, you’ve got two different kinds of seals for the pipes coming out of
the KERDI-BOARD. Again you can use Schluter KERDI-FIX to fill in this gap here, or you
can use the pipe seal. So once again, we’re just going to use the
flat side of the trowel to embed the pipe seal.
It’s 100% water-proof. There you go. So really only a couple of hours. I’m ready
to tile tomorrow. So this is a really fantastic way to water-proof your tub surround, and
it’s really kind of fool-proof. Anything you screw up, you don’t make a very nice
cut for any reason, just put a piece of KERDI over it. It’s not a big deal. So don’t
think if you didn’t cut straight or something’s off, it allows you to fix your goofs. Good
to go, thanks! All right, so that’s how you install Schluter
KERDI-BOARD in a bathtub or a shower. We hope that you like this video. If you did, give
us a thumbs up over on YouTube. That way somebody else can find the video, and it can help them
out. We come out with a brand new tutorial every single week on Friday, so you can subscribe
to our YouTube channel. And the other thing I wanted to tell you about
–and this is really cool—Steve and I work together to put Bathroom Repair Tutor up on
the Interweb. So why is Bathroom Repair Tutor so cool, and why would it help you out versus
watching videos here on YouTube? Well here’s the deal, when you subscribe to Bathroom Repair
Tutor, where you join, you get access to Steve and myself. So you could ask us questions
about your specific bathroom renovation. So not only do you get access to us, you also
get all the video tutorials that we collaborated on so you can watch those at your own pace.
And when you’re a lifetime member, you always have the ability to ask us some questions—anytime,
anywhere. So we really would love to have you as a member
of Bathroom Repair Tutor. It’s our passion to help inspire you to begin and complete
your bathroom remodeling project. So check out
Thanks again for watching this video. We’ll see you soon.

58 thoughts on “How to Install Schluter KERDI-BOARD in a Bathroom Part 2 (Step-by-Step)

  1. can you use any other waterproofing bonding compound such as TEC HydraFlex or Aqua Defense Mapei instead of unmodified thinset for better waterproofing the seams and corners?

  2. …also, I did not see a plastic vapour barrier on the framing sealing the insulation…before applying the kerdi-board? Where is this installation…I am in Canada..

  3. man its hard to find this here- Lowes only has the 32 x 48 to ship here, nothing at home depot and the local distributor wont sell to home owners only contractors- any other ideas? My shower is small maybe 36×44, so not sure if 32 x 48 will work

  4. Watched this & the Wedi panel. Seems a real ballache with the kerdiband having to set it in over every seam and every washer!
    I do like the way the kerdi board is all marked out to help with cutting & setting screws but the wedi system looked far easier with the ready mixed caulking.

    What's your thoughts on the two systems?

  5. Wediboard…only in the UK….Not in any local California Tile stores…
    I am sticking with the good old expensive and reliable Shluter-Kerdi-Ditra system
    And overlapping Shluter band in the corners are not a good idea because it is going to create a bump and you are going to have a problem to set your wall tiles even.
    I always get a kick out of these videos. They show how easy to set tiles. And we all know that is NOT that easy.
    However I can tell the gentlemen in this video is a great tile setter.

  6. One adjustment: Schluter says to use Kerdi Fix (sealant) on the tub lip then thinset above that when applying the Kerdi Band. Not thinset for both. The purpose of the Kerdi Fix is to seal the Kerdi Band to the tub lip and will adhere much better to the variety of tub surfaces than thinset will. It will prevent water from wicking up and thinset probably won't. The video on the Schluter website shows that detail. Good video here other than that one point.

  7. My outside  wall in my shower /bath alcove has been spray foam insulated between the studs . I will have 1/2" Kerdi board  over this wall , and am concerned about a double vapor barior causing potential mold?

  8. I was going to use the Kerdi mixing valve seal around my Delta mixing valve . I also have a Delta diverter , but Kerdi does not make a smaller seal for them . Should I just put the kibosh on these seals period ? I see you guys never used one on the mixing valve

  9. love this video. Was kinda apprehensive to start the whole kerdi install, but this makes it look like even a regular DIY Mom home owner can do it. Thanks. (especially like the thinset on his cheek when all done 🙂 )

  10. so dumb question here….in this series of videos on this job you only brought the kerdi board down to the tub flange, but on another video you guys did on a new tub install you shimed the studs out and said you were doing this to bring the hardibacker all the way down to the tub it's self. is there a reason for doing it two different ways….and what's the best way and preferred throughout the industry? thank by the way for you're videos and the replies to us newbies trying to learn the right ways!

  11. How can you fix a hole in the kerdi floor pan that already had the seal done and was ready to water test ? Had a 2×4 fall on it after I was done sealing everything

  12. your video didn't show how you seal between kerdi wall and Sheetrock ceiling. I only use kerdi for my shower walls and plan on painting my ceiling. should I use kerdi-fix for these seams or just leave it unsealed?

  13. I've remove tile over sheetrock from quite a few bathtubs notice I've said bathtubs and until now I haven't found any water going trough the tile sheetrock to the studs I know backer board kerdi board and and other materials are the best option for protecting against water but from experience I can say that if you don't have the money to do it this way you are perfectly safe using plain old sheetrock save yourselves some bucks and time and take the wife out to eat Saludos.

  14. That poor tub is scratched beyond repair. You’re fired on my job. BTW listeners he is using the wrong thinset Ardex 77 is a polymer-modified mortar. Schluter specs unmodified thinset for Kerdi band installation. I can’t watch anymore.

  15. Thanks for the info but did the actual bathtub survive the remodel? Seems the top surface of the tub took a serious beating, esp from that trowel.

  16. I'm sorry but the master plumber in me is saying "protect the tub, get out of there with your boots on without tarps laid down!! Nice job though..

  17. You did a great job installing the Kerdi and all of the band but if you work for me at fire you for not covering the tub protecting the tub no insulation no nothing and it's a cast iron tub how many of those do you end up replacing or repairing from scratching dinging?? Drop cloths are cheap!

  18. Nice bow chicka wow wow porno music. Why do you even need music it's distracting I hate when they do that this isn't a movie

  19. Any tile Setter knows you don't have to make it super flat a trail will do you don't need to sponge it clean because you're putting depending on the size of the tile half inch notch on the wall anyway up to three eighths or even a quarter inch the tile will find its level anyway even if there's a little bit of arise of say a couple millimeters of extra mud on the Kerdi band it's not a big deal so don't sweat the small stuff

  20. Looks like the warranty won't be upheld on this job. Just judging by your constant cuts to explain the proper process.

  21. hope that is your tub that you are doing if i see you doing that to a customers without protecting the tub you would be buying a new tub and starting over

  22. Thanks for making this video. Lots of great info & advise. Much appreciated. Hope ya have a great day & weekend. God bless.

  23. What about the seam from the kerdi board to the ceiling? Is it beneficial to put a band around the entire ceiling to wall seam?

  24. I see two things that are giving my pause here. First, you talk about adding water to the thinset after you've sealed the gap between the kerdi and the bath….doesn't adding water to cement like that after it's set ruin it? And why were you not putting the little discs on the seams between the kerdi boards like the manufacturer recommends?

  25. Question: if we dont have a tile flange, what would we do to keep water from seeping between the shower and the kerdi panel?

  26. I agree protect the tub better but this is a real life job. Tight area to work in all the little pain in the ass steps involved with bathrooms especially small ones. The constant clean up and endless buckets of mixing and clean water cleaning is endless. Recently did a 2nd floor condo bathroom with no hose bib or slop sink what a pain in the ass bid accordingly. Next time someone thinks contractors are over paid plz take a crack at this kind of work. It’s no office job but still comes with all the stress
    Now about that music that’s playing ??? What 1983 porn movie sound track is that ?

  27. Nice info – thanks for taking the time. I'm considering using this for a just-began remodel. Does the Kerdi-board provide enough strength? I'm worried about wall-flex. Should I be or is it fairly rigid?

  28. Hi can Kerdi and cement board be used together? I recently had the window in my tub replaced and the interior dimensions were about 1.5 inches smaller then the predecessor. In order to keep costs down and maximize structure around the window I’d like to use Kerdi for around the window and interior sill then concrete board for the remainder of my surround is this doable?

  29. So, if the kerdi board is fully waterproof, and tile/grout technically isn't waterproof, if the bottom of the tile is sealed to a tub with silicone caulking, where does the water go? Does it evaporate back out of the grout? I'm perplexed.

  30. I would recommend anyone watching this video to watch the Video from Schluter so you will install the Board correctly. I would also not allow anyone doing a job for me to be so messy in someone's home. The Schluter Video is – (Schluter®-KERDI-BOARD over Framing in Bathtub Surround Applications). I do thank you for taking the time to make this video, but why not slow down, ensure it's done correctly, and not so messy if you are going to post on YouTube. Pride of ownership and trying to perform your work better then all the rest is always very important to me. Haste often makes waste.

  31. Hi I copy this link, myself that I am asking questions to Starr Yolr and Starr Tile being mean said no…garbage talk. Below is the copy. Thanks.
    Hi what kind of thin-set do use and I Heard modified thinset will not dry on the waterproof shower system, is that true??

  32. Great video!! At the drain end were you transition from the kerdi to the flat purple wall. Do I need a stud at that joint!

  33. My wall studs are level but my tub is cockeyed causing the board not to be even how do I adjust that,Can the fix level that out at the top flange?Basically what I’m saying is the board sits flush with the flange and on the other side it doesn’t sit flush it’s like maybe an eighth of an inch or quarter inch off

  34. So, Ardex X 77 – is that an unmodified thin-set? An unmodified thin-set is required for Schluter Kerdi product install correct? Isn't Ardex X 77 a polymer-modified mortar? How do you get away with using it if it is not an unmodified thin-set? Doesn't that void Schluter warranty? Just trying to get it straight in my head. THX!!

  35. Loved the videos however I think I would have over lapped that kerdi band over the corner. It still would give you 2 inches on each side and it would make sure it does not rust.

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