However it works best for you. So long as you get a flat 100% bond.

The notches in the trowel simply allow you to get a measured amount of thinset on the wall. Not too thick, not too thin.

Trying to wrap a sheet around three walls in one shot could be considered ambitious, especially for a first-time user. That's a fair amount of thinset to spread and cover in a short time.

With Kerdi, so little thinset is used on the walls that it can skin over quickly.

Sometimes I run the membrane horizontally, sometimes I hang it vertically like wallpaper. Depends on the dimensions of the shower and where the seams will fall.

Yes, my thought exactly after having attempted it, ambitious! Ok, thank you so much we will take another stab at it.

Hope you had better luck today. I found that the first sheet I hung was... well, it went up, got a full bond... it was very messy though.** I did it vertically.

But by the third sheet, I was feeling good about the process... and it was my last sheet, alas. But then the shower base went quite smoothly.

**actually, DH thought it was too messy so he went and tried to scrub off the thinset that had made a bit of a mess on the surface, and ended up pushing the thinset away from the underside, I came back in and almost started crying- I ended up just cutting that section out and patching it with a >2" overlap. All good.

jjaazy,

Give this a quick look through, it might give you a few ideas on installation technique.

Well I am happy to report that we got one sheet up today. I won't share with you all the cool curse words that went along with it. Pepper my DH wants to know if you bench press 350! Oh, man it's hard to press in the Kerdi. But I am happy to say we got Kerdi brown! YeA! 100% coverage! We got it up and then used the hard edge of one of the floats to push it down and around. I can't seem to find my 4" blade since my plaster work but I will look again. The felt cover of the kerdi is a little ragged but no rips.
Mongo we took your advice and came up with a new plan of attack with regards to the sheet layout Thank you thank you! Now we will do two walls vertically and then we planed to shingle the window wall. This will mean that when I do that one corner one side of the corner will have 2 spots of 2" overlap meaning 3 layers of kerdi, is that ok? Or should I just continue vertically? We have 1 large window and 2 niches so it's easier to go horizontal on this wall. (I guess?)
Next I would like to know what you think about HD or Lws Modified Thinset products? I would like to purchase my Modified thinset from them if you think it is ok. Do you think the quality is ok for putting the Ditra down to the plywood? Is there a specific product/ brand I should look for? I thought I remember somewhere there being a problem with the quality of product at these stores. I want to share with you a story but will wait for now. : (

If you find that using the long flat edge of a trowel to bed the Kerdi too difficult, then try using the shorter flat end. Bedding the Kerdi into a flat application of thinset instead of notched thinset can make it harder to embed it too.

Three layers isn't a big deal, just feather each seam so you don't have excess thinset between the layers that causes unnecessary build-up. Kerdi itself is 8 mils thick, three layers is 24/1000ths of an inch not counting the two layers of thinset that bonds those three sheets together. So no, build-up shouldn't be a factor.

I know HD carries Custom's thinset, I think Lowes carries Laticrete. I've used Both and haven't had a problem with either. If I had to choose one over the other I'd choose Laticrete.

Whenever applying anything to wood, in this case Ditra over wood, yes you want modified. But when thinsetting to wood I also prefer adding a liquid latex admix to unmodfied thinset instead of buying the bagged modified. You'll get a better product.

You can buy Lsticrete's 317 unmodified thinset and mix it with 333 admix to adhere the Ditra to the ply. Then use 317 mixed with water to set the tile on the Ditra.

For Custom it'd be CustomBlend unmodified thinset and Custom Flex latex admix.

Mongo

I get how you fold the kerdi for the inside corners but what is proper method for the outside corners? Oh and do you do all four inside & outside corner joints in a Niche? TIA

I really can't be specific, as there are a few variations on outside corners, if you want to cut your own it's almost best to think like you're wrapping a gift.

In the "tutorial" I used preformed on the outside corners of the niche, and used a 2-piece to do an outside corner where an outside wall corner met the floor.

Are you looking at a different detail?

No, I was looking at yours, and I was just over at John Bridge trying to get a view of someone's else's project that showed niches and how they dressed the corners. It's kinda hard to see in the picture. Whatever I do there is going to be this unavoidable seam. I could probably make some outside corners and seal the seam with the caulk if that is necessary. We did the window and niche wall today. It is not complete but we are getting there. The one thing I keep reading is Kerdi doesn't rely on the shingle method to be water tight. So with your niche each one has 4 insides and 4 outside corners of kerdi right? It's hard to see the back of the niche. I am happy to say tho that the bedding process went so much smoother today. It looks really good thanks again for all your guidance.

Glad to hear you're getting the hang of it... pardon the pun ;-)

No, you can tell DH I can't bench anything, however I did have an extremely wet mix of thinset (not really intentional), and I used a big drywall trowel, I found the long edge and the leverage of the design easier for me... just a little physics, I guess. But I would love to compare curse words used during the process, I am sure they are similar.

I used the preformed corners, BTW.

FWIW, I did not like the Custom unmodified thinset. I had a lot more trowel fatigue with it than with others. I loved the Ditraset (unmodified), and the versabond (lightly modified for the drywall tiling) was fine. Perhaps it was my mixing, but I just felt like the ditraset was good at almost any amount of water, whereas the Custom one was a little less forgiving of my recipe; probably my inexperience in the end.

Where are the orange photos??

Let me know if these photos help clarify.

The first shows an outside corner dry fit. The second shows an inside corner dry fit over the outside corner. The third shows several of the niche pieces thinsetted, I whacked out the contrast on the photo to make them pop a little bit.

And you are correct, Kerdi overlaps do not have to "shingle lapped" for drainage.

Pepper right! (curse words) Agreed wet mix is the key we also give the thinset a light mist right before we hang the kerdi sheet. The next two sheets have been sooooo much easier. Mongo thank you so much yes you can see things so much clearer. Well I don't have the any of the pre made so will just make em. I don't see any in the upper back end of the niche is that right? So you only did outside corners on the upper part of niche?

You might want to check the box the drain came in. You usually get 4 incorners and 2 outcorners.

So you only did outside corners on the upper part of niche?

Yes. The horizontals are sloped for drainage, so the underside of the shelves see no water as it is. Plus they had a bit of Kerdi overlap from running the membrane across and down through the niche.

Thanks mongo just wanted to be sure. Bill I didn't use their drain so no outside corners. Do you think I should go get them? I have 6 spots that need outside corners. I don't want to come this far and cheap out now.

Thanks mongo just wanted to be sure. Bill I didn't use their drain so no outside corners. Do you think I should go get them? I have 6 spots that need outside corners. I don't want to come this far and cheap out now.

I would strongly suggest it. All it takes is a pin sized hole, and especially at the curb corners, without the preformed outside corners, you'll have one at each side.

Agree with Bill, especially on the floor.

The beauty of the preformed corners is that you know that the corners will be sealed, and that you'll seal them with a single additional layer of Kerdi versus a couple of layers that might be required by hand cutting and folding a corner.

Well, I used noble on the floor and did the corners as they showed. This question was in referance to the windows and niches. I will call them today and get the outside corners, maybe a few insides just to be sure there too. I gopped up the floor good with the sealant so I am 99% sure we are good there. But will definitly do a test. As always thanks.

That's right, you're doing the nobel floor with trench drain and kerdi walls, right?

Easily confused,
Mongo

alright, made the call. Does over 7.00 a piece sound right for outside corners? They first tried to tell me 19.00 each! After picking myself off the ground I said "that can't be right!" Btw I have been getting contractors prices but I found out HD now sells ditra and a smaller roll, better for us DIY'ers.

Mongo or Bill,

My tile installer is an old dog. He didn't use any of these preformed inside/outside corners even though I bought it and are laying in the box. He laid the Kerdi from top to bottom and overlaid the piece on the shower floor to where it connects to the shower wall. He said because the way he did, it doesn't need the inside/ourside corners. Neither it is needed in the niche.

I feel the same that I don't want to come this far and cheap out now but...given he is so certain about his way, I don't know how to insist, plus he has already halfway of putting the tiles on.

Do I have a valid reason to be concerned? Thanks.

Pro Source has outside corners for 15.37 and inside for 7.41.

That's for packages of TWO corners!

They shipped our huge order within hours and we rec'd within 48 hours.

They also sell Kerdi and Ditra by the foot, not roll.

Here is a link that might be useful: Pro Source

Carydan- go to the Schluter website and download the instructions/video, etc., it is clear. Did he make his own corners??

2" overlap at all edges

Also, John Bridge wrote a very explicit manual you can purchase and show him, or use Mongo's above referenced tutorial.

Yes, I ordered the Kerdi stuff from Pro Source and bought a few additional corners from eBay. And he knew it because when he first came I showed everything to him.

I even printed out the whole Mongo's post and showed to him. He said Mongo did it wrong 'cause he overlaid the lower piece to the top piece (he was referring to th niche Mongo did). He said the "right" way to do is to overlay the any top piece to the lower connecting pieces. I am not sure if it will make huge difference so I didn't say anything.

Obviously I dont want to hurt people's professional pride but...what I am trying to get is if this will somehow void Schluter's warranty should something went wrong in the future?

Thank you for the PS link, I found a guy today that would sell me 10 outside corners for 35.00 but another 35.00 for shipping. So that puts me back at the same price. I plan to call HD tomorrow, see if they can order it. Yes mongo on shower detail.

Next time you see him tell him if he really wants to know how to do Kerdi, he should attend "Schluter School".

They'll teach him that my methods were correct.

When you properly detail a Kerdi seam, which layer overlaps the other doesn't matter in the least. That said, if given a choice I'll "lap for drainage".

Properly lapped,
Mongo

But when dealing with several layers like on a niche, I'm not going to waste time weaving one partially set sheet over or under another. Because it simply does not matter.

Essentially, a properly detailed seam makes water intrusion a non issue.

At the Schluter School, they have a cardboard box covered with Kerdi. The Kerdi box has been there, holding water, for years and years. No leaking seams.

I hear you Mongo...

Sometimes I wonder if people here in the forum are little different than general population...lol..it takes certain personality type. He thinks people taking advice from online source are nuts I am sure.

I saw him the day before yesterday and yesterday. Of course I didn't say anything. Several things make me nervous...not saying I have to be right but...for example he kerdi'ed half way on the shower curb...I asked him why just covered the inside half of the curb but not the outside half of the curb...his reponse is that it wasn't needed...there would be shower glass and no water would ever be on the outside half...blah...true but...what if the tiles break in the future? To me if it takes 5 more min to cover everything than why not do it? I have enough kerdi...

Another thing is on the bath floor we did the DITRA and he laid floor tiles on it...but today I noticed that he might only butted the thinset on the back side of the tile, and nothing on the DITRA floor...because I could see the orange DITRA in between tiles...I was like...hmm I saw pics where people notches the thinset on a large area of the floor than perhaps put little bit thinset on the back side of the title and lay the tile...so I shouldn't see any orange stuff...now obviously he did differently...grrrr again.

I have to admit the tile work itself was pretty good, he did spent a lot of time and it looks great. Hopefully things like this won't matter in the end but it did make me nervous seeing his way. Let me know if I am wrong.

Thanks.

He thinks people taking advice from online source are nuts I am sure.

I hope you have a moment to call Schluter themselves and perhaps get advice directly from them; that cannot be ignored, right? They are mighty helpful on the phone, really pleasant to deal with!

Perhaps he did a better job than you are afraid of and you can be reassured. But you certainly raise some valid concerns.

I hope you are enjoying your new shower soon!

Are you saying he just Kerdied half of the top of the curb? It's not a huge deal in some ways, but in others it is. It certainly is a head-scratcher, especially if you had surplus Kerdi.

As to the ditra, the waffled recesses in the ditra need to be filled with thinset, it's the filling of those keys that locks the tile to the Ditra. If he just backbuttered the tiles and mashed it onto clean Ditra, that's not a good thing.

When I tile over Ditra I first use the flat edge of the trowel and fill the ditra keys with thinset. Then I use the notched side to spread notched thinset.

If the floor is to be a "wet floor" then he should have run strips of Kerdi over the Ditra seams. While the Ditra is waterproof, the butted seams are not.

Mongo,

I found an old pic that John Bridge did and it had kerdied half on the side of the curb. (http://www.johnbridge.com/articles/showers/kerdi-showers/)Granted, my guy didn't even cover the top of the curb -- onlt half...after I talked to him, he said he would cover all curb.

I can't stay at home all day and watch people do their work every min of it. I have to rely on them to do their a reasonaly decent job.

That was why I was concerned when I saw the "orange" between the titles but in theory, he could have just filled the Ditra keys with thinset in an area smaller than the tile, therefore after he laid the tile over, you still would see the orange Ditra between the tiles. Did he do that? Why did he do that? I have no way to tell. At this stage, it's too late anyway.

He originally didn't run strip of Kerdi over the Ditra seams. I insisted, showed him DITRA booklet and pic...he said, oh, they must change their way...:-)

Pepperidge, I did call Schluter and as much as they can help me on the "correct" way to do DITRA and Kerdi, there is no way to tell how bad or unconventional it is from someone's different techniques, unless examine in person themselves. For example, I knew my guys didn't use the inside/outside corners. He claimed the "way" he overlapped the adjacent kerdi...Schluter says yes you should use the preformed corner or make the corners yourself...so my installer obvious didn't do it by the book but how bad is it really? There is no way to tell. Is it worth to rip out all the tiles and re-do it? Probaby not...

So for the people trying to get opinion/advice, it's best to lay out your expectation with them and ask lots of questions before something becomes an issue. But even that, be prepared to have surprise...

I have decided to move on and not to think about it. Not worth to drill on it. Hope someone here learned something through my saga...

BTW, Schluter's number is 1-800-472-4588.

The curb in John's photo is what you want...the Kerdi lapped over the top of the curb and extending a bit down the outside of the curb.

And you can also see where John Kerdied the walls...then Kerdied the floor...then used a strip of Kerdi or Kerdi-Band to cover the open joint between the floor and the wall. Like mine, his isn't "properly overlapped" in the traditional sense, but that's okay, because Kerdi is a non-traditional product. 8^P

I just don't get guys installing Kerdi or Ditra incorrectly. I honestly think it's more work to install it incorrectly than to install it correctly.

If really installed incorrectly, and there is fair risk that the corners will not provide 100% watertight, then I would vote that before there is damage from those pesky H2O molecules, and it has to ripped out anyway, why not do it now, and the installer would have to be responsible?

There was a poster last year that had a beautiful shower installed and things started coming up almost immediately and ultimately if I remember correctly, there was but one screw hole on the curb top when the glass was installed that wreaked so much havoc that the whole bottom had to be pulled up, days to dry out, then reinstalled.

Best of luck.

Pepperidge Farm, I remember the thread. Or at least one like it. The one I remember, she had a nice shower enclosed with glass panels on three sides, the glass panels were set into a Kerdied and tiled curb.

There was a manufacturing problem with a glass panel and she needed it replaced. The glass guy removed and replaced the glass panel and in the process of doing so he destroyed the Kerdi menbrane on the curb, plus he never properly sealed the bottom of the glass panel to the curb for water-tightness.

She ended up with water running down the glass panel and getting into the curb...which caused the wood core of the curb to saturate and expand...and as the expansion occurred she had cracked grout and displaced tiles on the curb.

Her bathroom floor was a wet floor (Ditra and Kerdi) and with water getting into the curb it was able to reach the subfloor and wet the floor UNDER the ditra.

While she was able to get repairs made, that thread was a heart-breaker. It never should have happened.

yeah- that one. I knew it had to do with the glass, couldn't remember exactly the situation.

I think when it was all taken apart, she stated that it was a pretty small breach in the membrane that caused such a disaster... made me pretty paranoid doing mine.

The very lovely glass guys that came to do mine, I stood over them, cringed when they drilled through my Kerdi, and handed them my Kerdi fix to fill the holes. They were very patient with me hovering :-)

Hmmm, I never read that thread. Good you brought it to my attention.

What is the proper way to install show glass on the curb? I was thinking a cramp or two to hold the one fix panel (12" wide). The door is 24" wide and the hange will be on the side wall. I gave him a tub of Kerdi-Fix and when he left it's gone so I don't have any left. Should I buy another tube? or any substiute for this purpose?

Thanks again.

Many varieties of installation types. If one punctures the Kerdi, anywhere in the install, either intentional or accidental, one can either patch it (2" surrounding overlap) or small punctures can be kerdi-fixed.

So if you need to drill a hole for the glass hardware, just backfill the hole with the Kerdi fix before setting the screw. Kerdi fix is a I believe a Urethane caulk...

B. Schluter®-KERDI-FIX
1. Description: single-component, elastomeric, waterproof sealing and bonding compound with a silane-modified polymer base. Compound is free of solvents and odorless.
2. Color:
[BW - Bright White]
[G - Grey]

After looking over my kerdi walls I find around the window frame at the corner we have some areas that the kerdi did not adhere to the durrock. I outlined the areas with a marker and they are small a few are larger like from 1" x 2" to 3/4 x 4" I have 4 these areas are on same side of window not the inside frame but around the outside edge. Gosh I hate to cut into this stuff. What are your suggestions? I have some of the noble seal caulk I guess I could squirt some in there but "really do I have too?" I have another area but it lands outside of the wet area and on the other side of the glass area. TIA

So long as you're not using mosaics, and these areas aren't bubbled out to the point where they'd cause bumpos in the walls, I wouldn't worry about them. Any bigger than what you've described, though, and I'd think seriously about either slicing them and getting a little Kerdi-Fix in behind them, or cutting the area out completely and putting in a patch of Kerdi over the area, making sure to get that famous 2" overlap all the way around the patch.

Great! Glad to hear it, thank you again for bringing my anxiety down a few notches.

All...I hope the answer will be yes but is it okay to have some tiny unbonded areas as long as the surrounding areas are? I think putting up full sheets have been a little ambitious and I did have some areas where the thinset might have started skining over and did not spread and some areas where I did not have enough combed on...TIA

What do you call tiny unbonded areas?

little areas that did not "turn gray"...some "pockets"

here's a picture...

We found after scraping our first piece of kerdi, that we skim coated the entire shower first with thinset and let it cure overnight. Then made the mix extremely wet. Also sprayed the walls heavily with water with a spritzer, not so much that the walls had water sitting on the surface but entirely soaked. We also sprayed the thinset down a touch after applying thinset to durock. Then DH used the short side of the trial to push it down and around. I will tell you that we like pepper found that by the 3rd piece we were feeling better about the whole situation. Also DH was cursing far less then first sheet! ; )

I think I have it pasted pretty well except for a few spots where it did start to dry and some spots where I did not have enough troweled on in my haste...it's just not 100%...is the concern that the tile (and thinset over the ditra) would actually "peel away"?

Anything close to the size of the tile, I'd take out and patch. It's tough to see in the picture what areas are unstuck, but from your description, I wouldn't worry about it.