ABOVE: Hanging the second sheet. Measure for wall coverage, mark the wall, thinset the wall, and hang the sheet to the 2" overlap line marked on the first sheet. Embed into the thinset with the drywall knife.

ABOVE: Pulling the excess thinset out of the seam with the drywall knife. Don't leave too much thinset in the seam or you can end up with mini-speedbumps at each seam.

ABOVE: The second sheet fell short of the corner. Corners can be done in different ways. For this corner, I'll run a full width sheet of Kerdi through the corner and over the face of the niche, then cut it to fit the niche. The floor in front of the niche is wet from misting the cement board.

ABOVE: Slicing and dicing...

ABOVE: I could have cut these flaps shorter, but I'm just going to keep them full and fold them into the niche to see that they fit well with no wrinkling...

ABOVE: Then fold the flaps out, thinset the wall behind them, then embed them back in place. Again, these could have been done differently.

ABOVE: The second sheet on the niche wall is hung, sliced and diced, and thinsetted. There was a method to this layout madness. The second sheet was stopped about an inch away from the corner to the left, with enough overlap to get the required 2" over the sheet on the right.

ABOVE: Continuing on, each sheet is held about an inch from the inside corner, this open corner will be covered with a vertical piece of Kerdi, wide enough to get the requisite 2" overlap on each adjacent wall sheet.

ABOVE: Thinset applied with the flat edge of the trowel, then the ridges combed in with the notched edge of the trowel.

Great photos and insights. Thanks for taking the time to share this. It should prevent a lot of headaches for GW members who want to be sure they have a reliable, quality installation.

Schluter has a product called "Kerdi Band" just for this purpose. It's thinner than regular Kerdi. I'm just using a strip of regular Kerdi. I creased it lengthwise and set it in the thinset, using the edge of my trowel to tuck the crease into the corner.

ABOVE: Embedding it with a vertical swipe of the taping knife. If you press too hard with the knife and start pull the band out of the corner, you can hold the Kerdi to the wall with the edge of your trowel and then embed it with the taping knife.

ABOVE: Corner cleanup.

ABOVE: Back to the niche, I'll now run a piece of Kerdi vertically through the entire niche...

ABOVE: Dry fit to test the size...

ABOVE: Thinset...

ABOVE: Embed. Again I'm using the edge of the trowel in my right hand to pin the Kerdi in the corner, and the drywall knife in my left hand to embed the Kerdi into the thinset.

ABOVE: Schluter has inside and outside corner pieces. Here's where you need to control the amount of thinset you leave in an overlap, as the overlaps can get unwieldy. This piece is dry fit on the edge of this niche, it can also be flipped around to cover and outside 90-degree corner.

ABOVE: Here's an inside corner piece dry fit over the other piece. This piece can also be flipped over and used to cover an outside corner. These corners can be done differently. Again, the purpose of this was to show different ways to get things done.

ABOVE: The first piece thinsetted in. Again, using the trowel to pin the corner piece in place while I use the knife to embed it in the thinset. And again, just a technique.

I'm sure many will be as grateful for this as I am. I find it fascinating.

ABOVE: Corner pieces and overlaps can add up. If you leave excess thinset between overlaps with no corrections made, the fat overlaps can throw the tile alignment out of whack.

ABOVE: Going back a bit, this niche was site framed, the shelf framing was pitched. Then it was skinned with cement board, and the cement board skim coated with thinset to clean things up a bit. With the framing being pitched for drainage, the cement board is also pitched for drainage.

ABOVE: Personal technique. With the exception of the bottom course of wall tile, I tiled the walls and ceiling before doing the floor. This way I can create mayhem and madness without damaging the shower floor.

The plywood subfloor was covered with a slip sheet, in this case, 6-mil poly. Then that was covered with metal, the metal stapled to the subfloor.

Obviously, instead of deck mud, a manufactured Kerdi Tray could be used on the floor. The K-T gets dry fit for fit and drain alignment, then it gets thinsetted directly to the subfloor. No poly, no metal mesh/lathe
.

ABOVE: Installing the sloped deck mud. I go for about 1-1/4" thickness of mud around the drain and slope it up to the walls. The slope of the mud should be between 1/4" per foot and 1/2" per foot. I first set the perimeter elevation by packing a rim of mud around the perimeter of the room to the required elevation. Deck mud is about a 5:1 ratio of sand:portland cement. Add just enough water so it has the consistency of sand castle sand. You don't "pour" it in place like concrete. Because it's a dry mix it does not flow. You put it where you want it and "pack" it in place, I use the wood trowel.

ABOVE: With the perimeter of deck mud set around the base of the walls, I'll set a ring of looser mortar around the drain. The Kerdi Drain flange will be set into this ring.You can see the drain flange in the bottom of the photo. I covered the fleece with masking tape to prevent is from getting messed up during installation.

ABOVE: Fast-forward, the drain was set to the proper elevation, and with the room perimeter having mud packed to the proper elevation, the floor space between the drain and walls was filled with deck mud. It was packed to the proper slope and smoothed, then allowed to cure for a few days.

ABOVE: Dry fit the Kerdi to the floor. You don't want a seam falling on the drain flange. For this installation, I'll just Kerdi the floor itself and then bridge the open floor-wall corners with a band, similar to the wall corner done way back when.

ABOVE: Floor sheet rolled up and thinset placed on half the floor.

ABOVE: Floor done. 2" overlap at the seam with the seam not falling on the drain flange.

ABOVE: Covering the floor-wall corner with band. Dry fit. Again, just another technique. I could have used one of the manufactured corners that I used in the niche. To do it as shown in the photo above, snip the floor fold and fold one lap over the other. You'll also notice that the part that rolls up on the wall is not "lapped for drainage" with the membrane already on the wall. Being lapped for drainage is not a concern with the thinsetted Kerdi seams. As long as you have a 2" overlap the thinsetted seam is watertight. Remember the seam on the floor that is flat? Watertight due to the 2" overlap.

ABOVE: Outside floor corners, again, this is a different piece provided by Schluter.

ABOVE: Set it on the floor and set it firmly against the corner so it rides up the wall a bit. It'll get thinsetted in place and then...

ABOVE: This piece will cover the piece shown in the previous photo (which is removed in this photo). With the other piece riding up the wall a bit and this piece riding down on the floor a bit, the corner gets covered. I'll usually put a shmear of Kerdi Fix sealant on these corners for added insurance. And again, this outside corner could have been covered with a manufactured corner, similar to one used in the niche.

ABOVE: The above pieces all thinsetted into place. Control your thinset to control the thickness build up. Corners like this are where liquid membranes are easier, as you paint the membrane on instead of having to worry about overlaps. Still, sheet membranes are not overly difficult. The installer just has to respect the process.

ABOVE: For something a little different, this shower has a raised platform outside the shower door that is used as a drying off platform. It's also used as step to get into and out of the tub that will eventually be installed to the right. So the platform got cement board and Kerdi.

ABOVE: This floor is being covered with about 4" squares cut from larger 12" square tile. For layout, the floor was gridded into about 12" squares.

ABOVE: Floor tile cut from larger tile, fresh off the wet saw...

ABOVE: Floor tile thinsetted down, dry fitting the border at the shower entry.

ABOVE: Floor tile in, bottom course of wall tile in, and grouted. This tile has a clefted slate-like texture, so grout clean up was a little bit more effort than typical.

ABOVE: Done.

Mongo - our MBR is 2 ½ years done (and no problems at all) but I still would like to say how much I appreciate both this thread, and your generous and helpful comments through the years.

Great detailed post Mongo. I'm sure folks will benefit from the walk through you have provided.

WOW, thank you so much for reposting this great thread. You are always so helpful. I can't thank you enough for all the help you have provided me over these last few years.

This is still daunting to me, but WOW. Thank you for spending the time to help educate us. Great resource.

Thanks for the kind words. I still get emails asking if I can provide copies of the pics missing from the old thread, so hopefully this will help me and others out a bit.

So glad I asked. Now I have so much studying to do so I can understand what I need to look out for. Great to have the whole thing here for reference. Thanks again Mongo.

You're welcome. Your post was the inspiration for the mulligan!

Great post Mongo. Thanks.

Mongo is editing your old post an option to link to this new complete post. I would think reviving the old post by referencing the newest post could be confusing and cause both threads collecting comments.

Joe, thanks.

Enduring...how are you! Brilliant idea. I couldn't edit those old threads, so I just added a post to them referring people to this thread. Unfortunately, adding a post will revive those threads. But they should drop off the front page quickly.

I was reluctant to start yet another Kerdi thread, but I probably get two or three requests a week for those photos. We can blame it on rococogurl! lol

Yes, let's blame rococo! Ha!

I have been fine. I am wishing that I had a remodeling project :( I'm pretty much done with this old small farmhouse.

BUMP

I'm so grateful for this information.

I have some basic questions. I think we're at the point where the water test should be done. Were using a general contractor who we verified had both extensive training and certification in the Schluter Kerdi system and also provided extensive photos of other jobs ( in proposed and completed) that matched what I found online.

At this point, the shower floor is about to be tiled. Isn't the water test supposed to be conducted first? Or...when? My sister had a very small leak during the water test ( different contractor, different state) and it was repaired.

I'm concerned because the tiles are scheduled to be installed but there Ben no water test first. Until now, the tile guy has been a perfectionist, even taking time to redo some areas we didn't know had issues, etc.

Should I be concerned ? I've researched extensively but could have missed something.

If he doesn't test beforehand, he could be tearing out a lot of tile if he does it afterward.

Thanks so much for this input! That's what I thought but every time I raise the topic the tile guy says " My showers don't leak."

But from what I've read, omitting the water test could void the warranty. ( I'd take photos of the test.)

Until now, there haven't seem to have been any shortcuts. I've researched and have seen how he's taken extra time to adjust metal trim on a niche ( the trim part of the Schuter system and obtained directly through Schluter ) and wall tiles when they didn't meet his standards.

So this is baffling.. I know it means waiting longer to him to get the final payment for the redo but I want this done right - per the contract.

"but I want this done right - per the contract."

Does the contract state a water test is to be performed?

The contract calls for the system to meet all warranty requirements. When I called Schluter it said that a water test was an integral part of the system to fulfill the warranty .

Get it in writing from Schluter and show it to the tiler...................

They're doing the water test.

Interesting thread. I'm in the same place - tile setter has done a wonderful job so far on the walls outside the shower. He will be using the Kerdi shower system, but I think he will be doing a mud pan and not the prefab Kerdi board pan. I asked today about a flood test, and he says he doesn't do them and they are not required. I've done some research and found that many folks on the JB forum question the need for such a test with the Keri/Schluter system. I know Mongo was one name I saw on the JB thread. I checked the Schluter warranty and didn't see anything about a water test requirement being required for the warranty to be valid. So what's the deal?

I didn't flood test the only Kerdi pan I did several years ago. It seemed silly. I knew that thing couldn't leak. No callbacks yet.

Pan water testing is so easy. I can't imagine skipping this. My testing has revealed a few leaks over the years mostly in a fold or a outside corner patch. I don't recall a drain assembly leaking. I usually plan my quiting time around the test set-up and invite the customer to participate. It's the pin hole leak that may take an overnight test to show itself.

IRC requires a flood test be performed for bonded membrane showers, Kerdi is a bonded membrane.

Short version: Plug the drain, fill the pan to a 2" minimum water depth at the threshold. If required, build a dam at the threshold to get the required 2" depth at the threshold. Observe for 15 minutes minimum. Drain. That is what code requires.

I have no idea why anyone would be resistant to do a flood test if the homeowner asked.

Fixer, I'm trying to figure out how this doesn't cause at least a two day delay in the project. You are supposed to wait 24 hours after the kerdi is laid before doing the test, then I assume you need to wait another 24 hours for it to dry before tile? If this falls on a weekend it's fine. But if not.....

I'm not saying it isn't good insurance, but from a practical standpoint am I right in terms of the scheduling issues it could cause?

I'm not sure my tile guy will argue if I want it done, but my GC who hired him could be really put off. Contract says work will be to code which is apparently not an issue here in MD.

Wow. 50 hours and then it leaked? Makes me wonder if its worth the time and effort if it could still be all for naught. But my tile guy agreed to do the test. Not sure how long we'll let it sit, but at least overnight.

Our water test has been successful. It's been over 2 days and as we head into the weekend it will be drained in prep for the next step. Every day that's gone by has been a comfort. The water level hasn't gone down, at least not below normal evaporation ( minor)

Here's a comparison: a friend had the same system installed. The contractor insisted the water test was not necessary. There was indeed a leak. . But not discovered before the tile work on the floor was started.

i don't understand why a water test is seen as a "delay" when it's required to meet warranty terms. Or did the Schluter Kerdi phone rep provide incorrect info?

And I took photos of our test and will have written confirmation , etc.

Here is the most important part of a successful flood test

be present when the plug is pulled watch closely that all the water drains and there are no puddles or pooling anywhere after 20-30 mins it should be close to dry Congrats and best of luck

jcorn1 - Glad your test was successful! And sorry to hear about your friends problem. Curious though as to how they knew it had a leak when the tile had been started, but not finished. Did they do a test then with only part of the tile laid but the shower not finished? Was their install done by someone with Schluter experience or was it a DIY job? Just curious.

I will have a water test done by the tile setter, but I doubt it will be a 48-50 hour test! What I may do is a test of my own for that extensive length of time AFTER the shower is completed. I have a one year guarantee, and if that shows a problem, I would call them back quickly and make them rip it out and redo it. And hopefully we could still get extra tile to match the rest of the room at that point.

Not sure about the Schluter warranty info you got over the phone. All I could see on their website was info saying that doing such a test was "recommended". I looked at the warranty info on their website and didn't see anything specific about a water test; it just said material had to be installed in accordance with the handbook and "industry standards". The install handbook says that water testing is "strongly recommended to verify a successful installation". I guess they would point to that, but other sections of their website and literature make a big deal about how you can set tile right away. In one place, it says water testing MAY be performed and says it is a BEST PRACTICE. And the water test is technically not part of the install and would not affect the outcome - its just a way to verify a good install. It could be that if water testing is required by local code, they would point to that as a reason to void the warranty, but otherwise I think it would be a tough argument. In any case, there's no way I want to experience a failure after the tile has been laid, so I agree that it's good insurance - but definitely not a 100% sure thing if failure may only show after 50 hours!

numbersjunkie-

Calling someone back to rip out the tile, redo a leak somewhere, redo the waterproofing to merge flawlessly with adjacent non-demo'ed areas, and re-tile and re-grout so that it blends perfectly is a huge job requiring A-team skills and a positive mindset. Presuming you could actually get the warranty honored, and that you had matching tile, and that the contractor had the skills to redo perfectly what he screwed up the first time, and that the rework didn't cause new problems, it's still a huge hassle.

Me? I'd do the flood test first. Just because a rare flood test didn't show until after 48 hours doesn't mean that the other 99%+ aren't worthwhile....

kudzu, yes we will definitely be doing a flood test. Just not sure it will be for 24/48 hours because the tile guy has other jobs backed up in the queue due to my job already taking longer than expected. But I will do another 50 hour test as soon as possible after the shower is complete, just in case we need to buy more tile for a shower re-do. I agree that its worthwhile, but still not a 100% guarantee. As they say, nothing is certain except death and taxes!

Glad to hear it. I was afraid you were talking yourself out of doing any test at this stage. Even a slightly shorter test is worthwhile....

Turns out ours will actually reach the 50 hour mark, maybe a few hours more, before the plug is pulled. Fine by me and possibly shows the contractor's confidence.

Numbersjunkie. I test the pan before mud is put down.

fixer687 this is a topical waterproofing system. No pan no liner and possibly no mud.

CTE. I was responding to Numbersjunkie's comment.

Is this thread not about Schluters Kerdi system? 2yrs ago it was a very detailed post by mongoct. Now it appears to be about flood testing Kerdi unless I missed something. Which is always possible:)

And also Mongo T addressed the water test on this thread( although it's old) , leading me to believe it was not unreasonable to conduct a water test in some situations. . Since I am not personally installing my system, I don't have the confidence of someone who knows exactly what to do to ensure it is watertight without a water test ( other than watching every step my contractor completes and comparing those steps to Mongo's photos)

Anyway, it seemed relevant to mention it in a thread which covers - among other topics- the subfloor and tile.

[https://www.houzz.com/discussions/kerdi-flood-test-failure-what-now-dsvw-vd~2332223 [(https://www.houzz.com/discussions/kerdi-flood-test-failure-what-now-dsvw-vd~2332223)