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Kerdi Shower

Posted by mongoct (My Page) on
Sat, Nov 17, 07 at 11:35

Okay,

There are ways and there are ways. This post shows a couple of ways to do it.

Shower is a walk-in, about 5' by 7'. Door is at a 45 degree angle.

Walk in to the shower and on the short wall to the immediate right are two supply valves, the lower one supplies the wall mounted handheld, the upper supplies an overhead 12" rainshower head.

Moving counterclockwise from that wall, the long wall on the right is on an exterior wall, nothing but tile.

The short back wall has a 2-shelf niche, about 36" wide and 30" tall. The lower niche space is 15" high, the shelf itself is 4" thick, the upper niche space is 11" high.

The last wall, the long wall to the left as you enter, has the wall-mounted hand-held. If I recall, the sliding bar is 40" tall.

Tile backer? I prefer cement board on the walls. Wonderboard or Durock. I used Wonderboard on these walls. The ceiling and niche is done in Hardie, as Hardie is less brittle so for me it's easier to cut into narrow strips to trim out the niche, and not as prone to snapping when installing full sheets overhead.




Follow-Up Postings:

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Kerdi 2


ABOVE: Need to get the walls smooth, so I'm knocking down high areas or any blobs or thinset with a carborundum stone.


ABOVE: Setting a plumb line to hang the first sheet. Just like hanging wall paper. I hold the first sheet about an inch from the inside corner. Sheet is about 39-1/2" wide. I want the thinset to extend about 1" past the edge of the sheet. So I drop a plumb line about 41-1/2" or so from the inside corner, and mark the line vertically every foot or so with a tick mark using a sharpie.


ABOVE: Thinset. This is a little thicker than I want. I want it stiff enough so I can flat trowel it on the wall without it dripping all over or running down the wall, as well as it being able to hold a ridge after it's combed out. Not too stiff, though as you don't want it skinning over before you hang the sheet.


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Kerdi 3

ABOVE: Misting the walls prior to applying thinset. I thoroughly mist the walls, then I mix the thinset. While the thinset is slaking, I cut my Kerdi to size, then lightly mist the wall a second time.


ABOVE: Working quickly, I flat trowel the thinset on the wall, using my Sharpie marks as a guide. I work bottom-to-top, as I find the incandescent lighting can accelerate the thinset skinning over.


ABOVE: Once flat troweling is done, I comb the thinset with the notched edge of the trowel, again working bottom-to-top.


ABOVE: I quickly get the Kerdi over the combed thinset, I hold it plumb, then lightly run my hands across the top of the sheet, then down the middle of the sheet. Just enough to adhere it to the thinset. I then work top-to-bottom and run my hands from the center of the sheet to the edges, lightly bedding the Kerdi in the thinset.


ABOVE: Kerdi is bright orange. Once it's bedded in the thinnset, it turns a muddied brownish-orange. After hand setting the sheet, I use a 4" taping knife to thoroughly embed the Kerdi in the thinset. I run the knife at a low angle, with a bit of pressure, working in the same manner that I initially set it with my hands...top-to-bottom, and center-to-edges.


ABOVE: Process repeated for second sheet. Kerdi has printed lines 2" (50mm) from the edge of the membrane to assist in getting the proper overlap. this shot shows the second sheet going up, you can see the sheet going from bright orange to muddied orange as I work it into the thinset.


ABOVE: This bright orange spot indicates no thinset behind this part of membrane. I'll use the taping knife to draw some thinset from adjacent areas to this spot.


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Kerdi 4


ABOVE: Niche shelves are pitched for drainage.


ABOVE: This shows two things. First, you can run the membrane through a corner as shown in this picture. Just make sure that your corners are plumb...which, in a shower, they sure as heck better be...so that the plumbness of the sheet isn't thrown off as it transitions to the next wall. Back to the niche. For now I run the membrane right over the face of the niche, I'll come back in a bit and...


ABOVE: ...slice through the membrane with a sharp utility knife.


ABOVE: Prior to applying thinset to the inside of the niche, I dry fit the membrane flaps inside the niche to make sure they fit well.


ABOVE: Flaps bedded to the back of the niche with thinset.


ABOVE: Left side done same as the right side.


ABOVE: I cut a piece of Kerdi as wide as the bakc wall of the niche, and long enough to start above the niche opening, run through the niche, and run out the bottom of the niche. Dry fit.


ABOVE: Thinset.


ABOVE: When working on inside corners, use a tool in each hand. Use the edge of one tool (I use a trowel) to hold the Kerdi membrane in the inside corner, and the other tool (my drywall knife) to bed the Kerdi in the thinset. Were you to just use one tool, you'd pull the membrane out of the inside corner. Frustrating and time consuming, to say the least. I'll come back and do the niche corners later.


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Kerdi 11


ABOVE: With the previous corner, I ran the membrane through the corner, from one wall to another. With this corner, I held the sheet on each wall about 1" or so off the inside corner.


ABOVE: I cut a length of Kerdi about 8" wide, enough to span the two inches of naked cement board in the inside corner and then run 3" over the already hung membrane on each adjacent wall. This ensures that I meet the 2" minimum overlap. Regular Kerdi is 8 mils thick. Kerdi-Band, a product designed for just this purpose...spanning from one sheet to another...is 4 mils thick. Most of the time I use regular Kerdi for corners like this. It depends on your ability to cope with the thickness of additional layers of material as you set the tile. For the materials I was using in this shower, the added thickness of Kerdi would not be a problem. Anyhow...thinset the conrer and comb it out...


ABOVE: Crease the sheet down the middle, then hang it in the corner...


ABOVE: Bed one side in the thinset, bringing the excess out through the overlap...


ABOVE: Then the other side.


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Kerdi 13

Back to the niche...When you buy a Kerdi Drain, a few preformed corners come included with the drain. Usually. Some resellers have been known to open the drain box and remove the corners and the installation DVD and sell them separately. The preformed corners can also be purchased from Schluter. Anyhows...


ABOVE: This shows one type of preformed corner dry set on the edge of the niche.


ABOVE: And here's another type of preformed corner set on top of the previously set piece. Here it's uysed as an inside corner. Note that this corner piece could be flipped over to cover an outside corner, too.


ABOVE: Trowel, then comb the thinset. Then the dreaded two-tool method strikes again, the edge of the trowel is used to hold the Kerdi piece in the corner while the drywall knife is used to bed the corner piece into the thinset. Note the thermally fused seam on this piece, the seam that runs away from the trowel at a 45-degree angle. The fused seam results in a slight ridge or bump along the length of the seam. That can sometimes be a pain as the raised seam can catch on the trowel and it can pull the piece out of the thinet.


ABOVE: Hallah-freakin-lu-yah. The niche is done.

One thing to note is that the preformed corners are essentially designed for perfect 90-degree corners, though they can be tweaked a bit. In the case of the niche, where the shelf is slightly pitched, you do have to work the corner piece a bit to get it to lay flat on all three walls.

Minor quibbles, but hey, it is what it is. Overall, the preformed corners are handy, but expensive. I cut my own corner pieces for the floor, I'll show those later on. Those pics are on the other computer, so it may be a bit before I get to them...


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Kerdi 22

Fast forward...the walls, niche and ceiling are tiled and grouted. Time for the drypack preslope...


ABOVE: Old 2-part clamping drain cut out, I bought a $3 cutoff wheel and fashioned a jig to cut the drain from the pipe from the inside. Match your Kerdi drain to your existing plumbing, ABS or PVC. You can see PEX for radiant floor heat underneath subfloor.


ABOVE: Underlayment scewed, new drain location set. Though it depends on the height that the Kerdi Drain is set at, the Kerdi Drain flange is about 4-1/2" in diameter, I cut a 5" diameter hole in the underlayment and subfloor.


ABOVE: Setting the perimeter elevation for the drypack preslope. I base this height on a 1-1/4" thickness of deck mud under the flange of the Kerdi Drain, plus an additional 1/4" rise per foot of run from the drain to the farthest wall. I actually pitched this floor slightly steeper, as the floor tile has a bit of texture to it, slightly hindering drainage.


ABOVE: More mud packing.


ABOVE: I make the mix slightly looser for the ring of mud that goes under the drain's flange.


ABOVE: I covered the fleece surface of the drain with masking tape so the fleece wouldn't get messed up during installation. I had previously dry fit the drain to the plumbing waste line. The coupling sitting on top of the drain is cut to length so the drain will be set at the proper height above the subfloor, 1-1/4" in this case.

You have to have your ducks all squared away when glueing the drain to the plumbing waste line while simultaneously mudding the drain flange in place, as the flange has to be set at the proper height and set perfectly level.

It's much easier if you have access to the plumbing from below and you can simply set the drain flange in the mud on Day One, then glue up the drain to the waste plumbing on Day Two after the mud has set.


ABOVE: Fast forward, the preslope is completed. The drywall bucket is sitting over the drain.


ABOVE: A well set drain in a properly pitched preslope. Time for a beverage of my choice.


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Kerdi 23

Time to Kerdi the preslope:


ABOVE: First sheet is dry fit to the preslope. You don't want a membrane seam to fall on the flange, so plan accordingly.


ABOVE: Drain kit comes with a template to cut a properly sized hole for the drain in the membrane.


ABOVE: Hole is cut, I also used the ever-present Sharpie to make tick marks just off the edge of the sheet to show how far out to spread the thinset.


ABOVE: Roll the sheet up...


ABOVE: Spread the thinset...


ABOVE: Same bedding technique as used on the wall, and viola, the floor is done. Now time for the floor-to-wall transition.


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Kerdi 25

The floor-to-wall transition. When you have a lot of inside/outside corners, this is where layers of Kerdi can build up. Remember, Kerdi-Band is half the thickness of the regular Kerdi, so that may help. Thickness buildup, to me, is dependent on the type of tile that you're installing. A 1" mosaic, for example, would telegraph and mimic the height differentials that a larger tile could span and disguise.

Plan accordingly.


ABOVE: Starting with an inside corner. Pre-crease the material, snip, fold, and place. These inside 90's are easy. Move on to the next corner.


ABOVE: I use the ever-present Sharpie to mark the inside or outside point of all corners, then use scissors to cut just shy of that point. Fold the material hard over on itself to the Sharpie mark, and it is sort of self-sealing, so to speak.


ABOVE: Cutting to an inside 45 degree corner. Pretty much the same as a 90.


ABOVE: You can see the previous 45 folded over on itself, I'm now marking an outside 90 degree corner. This requires an bit more detail.


ABOVE: Here is the first piece for an outside 90. You sort of force this piece around the corner so the uncut inside edge rides up the wall a bit.


ABOVE: Like this, but when installed it'll ride up the edge of the wall just a bit more.


ABOVE: When the previous piece is installed, this part will go over it, layered on top. Whereas the previous piece sat on the floor and rode up the corner of the wall a bit, this piece cut will be on the wall and the cut will ride down on to the floor a bit. The two pieces will overlap, closing the hole so to speak.

Now, while I trust Schluter, I also want peace of mind, so I use a smear of Kerdi-Fix in these corners as well. Kerdi-Fix is Schluter's proprietary sealer. Comes in a tube like caulk and is dispensed with a caulking gun. I let everything cure/dry, then use the K-F prior to tiling.

Like Agent Mulder, when it comes to water intrusion I pretty much trust no one...


ABOVE: This shows all those corner pieces thinsetted in place. As you can see, the layers can build up, so consider using the thinner Kerdi band or the preformed corners if you need to minimize thickness.


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Kerdi 26

Now for something a little different. I'll include this since it's Kerdied as well.

Instead of a simple curb at the entry to the shower, I fashioned a larger platform that serves as both the curb for the shower, a raised tiled "drying off" area just outside of the shower, as well as a step up to facilitate getting into and out of the Jacuzzi tub.


ABOVE: Platform is framed, covered with two layers of ply, and more of the wondrous Wonderboard.


ABOVE: Platform is Kerdied, and platform Kerdi is lapped over Kerdi in shower.


ABOVE: "Curb" and platform from inside the shower looking out.


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Kerdi 27

Time to tile the floor...


ABOVE: Grid layout is for floor tiles, each square is about 12" square. Each square is large enough to fit a 3-by-3 grid of ~4" tiles. Remember, the floor is sloped, so grout joint spacing needs to be adjusted ever-so-slightly to keep straight grout lines on a sloped surface.

The drain cover for the Kerdi Drain is about 4" square, so it matches this tile size quite well.


ABOVE: Ah yes, a fun morning spent with the Felker wet saw...


ABOVE: The 4" field tiles layed out and thinsetted.


ABOVE: Filling the border tiles around the edge of the field of 4-inchers, right in front of the door.


ABOVE: The floor along the opposite (niche) wall. You can see the drain. Sometimes the drain can be set as if it were a whole tile, replacing a single 4" square tile, or four 2" square tiles. For this floor layout I clipped the corners of the four adjacent tiles to fit the drain into the center of those four 4" tiles.


ABOVE: Filling in the remainder of the floor tiles in front of the door opening, as well as the "baseboard", or bottom course of wall tile.


ABOVE: The tiled floor.


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Kerdi 28

Almost there:


ABOVE: The fun part.


ABOVE: Done, from the inside looking out.


ABOVE: Done, from the outside looking in.


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Kerdi 30


Miscellaneous leftovers:


ABOVE: Someone asked if I had a picture of the squeeze out I get at the seam when I use the drywall knife to embed the Kerdi in the thinset. Here's a close-up.


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RE: Kerdi Shower

What an amazing public educational service - thank you for posting. I only hope my contractor's tile guy is this detail oriented!


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RE: Kerdi Shower

Awwwww, I coulda done that. :-)

Nice job, Mongo. REAL nice job.

One comment, though-- you're the first person I've ever seen that hangs the Kerdi vertically! Not that it's wrong (it's actually a pretty good idea for wrapping around the corners), but just curious-- how'd you get started hanging it like that?


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RE: Kerdi Shower

"...you're the first person I've ever seen that hangs the Kerdi vertically! "

No kidding?

Working alone, to me it seems vertically is easier. Just like wallpaper.

One of those things you never really think about until someone makes you think about it!

Mongo


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RE: Kerdi Shower

Wow! I can only echo tartanhabit--an amazing public service. Thank you so much. My husband and I spent a few hours today ripping out work already done by our (former) contractor in preparation for the Kerdi shower/bathroom we are now planning. Your pictures and instructions are way beyond anything I expected to find, and your shower is gorgeous! You are terrific!


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RE: Kerdi Shower

You really meant to write I'm gorgeous and the shower is terrific, right?

Hah!

(thanks!)

Mongo


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RE: Kerdi Shower

But of course!


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RE: Kerdi Shower

Thanks!!! This is just fantastic; very, very useful.


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RE: Kerdi Shower

would you install my shower...in california??? do you know anyone in the s.f. bay area who works as meticulously as you? beautiful job on the shower, and thanks for taking the time to show us "how to"...now i'm waiting to see what bill comes up with as his "how to" :)


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RE: Kerdi Shower

rachel-- There are actually several tile installers from the Bay area over at John Bridge's forum. Most of them are very familiar with Kerdi and do excellent work. What you might do is go to the following link-- it's the forum over there known as the "pros hangout". Post a message over there looking for an installer in the San Fran area. I don't think it'll take too long to come up with a good installer.

Here is a link that might be useful: John Bridge's Pros Hangout


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RE: Kerdi Shower

thanks for the "how to" bill...touche!


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RE: Kerdi Shower

Mongo, are you psychic? This post is awesome as I'm about to embark on my first Kerdi shower within the next month or so.

Thanks so much for sharing this!


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RE: Kerdi Shower

You welcome! Best of luck with your project.

Regarding "psychic". A slight tangent. A friend was over tonight with her 5-year old daughter, we were playing a card game. The 5-yo had a card with "psychic" written on it. She was eager to give the word a try, her Mom beaming with envy that her daughter can pronounce such difficult words at her young age. How did she pronounce it?

"pissy chic"

We all had a good laugh.

Are you doing a mud pack preslope or using a Kerdi presloped pan?

Mongo


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RE: Kerdi Shower

LOL. Kerdi job in my future too; DW's getting psychic. At this point I plan to use the Kerdi pan, though I'd sort of like to try a mud pan for fun. One thing I've recently been thinking about and which may dictate a mud pan, is elminating the curb. Is it nutty to re-do the floor support system so the drain is below floor level instead of raising the rest of the bathroom floor?

And yes, thanks for the tutorial - I know that took a lot of time to put together.

Thanks,
Bill


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RE: Kerdi Shower

My stepson, when he was little was slightly psychic. My wife could hold up playing cards, and he could guess them with a constant 80% accuracy. When my wife told him the term for his gift, he just stored that little piece of information away, until the next time they went over to my wife's parents' house. He couldn't wait to tell his grandparents that he was psychotic!!


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RE: Kerdi Shower

Bill G,

No, dropping the floor is not all that our of the ordinary. As long as you have the depth to do it. I've also made the curb a "hump" in the floor, a couple of inches of rise spread out over 18" or so of run. Depends on how much floor space you have. Makes it easy to roll a wheelchair into the shower.

Bill V,

Hah!(g)


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RE: Kerdi Shower

This is just brilliant! I want my shower done this way. Is it significantly more expensive than the usual method?


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RE: Kerdi Shower

Probably about 2.50- 3.00 a foot more, labor and materials, plus the cost of the drain, which is about 80-100.00 depending on which finish and where you buy it.


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Stupid question...

But what exactly is the advantage of a Kerdi shower?


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RE: Kerdi Shower

The biggest advantage is IMMENSELY increased longevity. Because of the fact that it's a topical membrane, and it's a waterPROOFING system, as opposed to the vapor barrier that most showers have, the only thing that gets wet is the tile, grout, and thinset. It doesn't get into the cement board, or the mud, nor does it get into the wall cavity, so there's no way for moisture to give you any terrible surprises a few years down the road. Without a doubt, it is THE best shower construction system around.


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RE: Kerdi Shower

Wow, just saw this. This is so immensely clear and helpful...thanks so much, mongo. I'm saving it just in case we ever have to do another shower ever in our lives...at this point I'm hoping *not*, but you never know LOL


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RE: Kerdi Shower

mongo, i got a ticket to Philly waiting for you!!!! What a craftsman!!! I can only hope i get a job 75% of what you do...Having recently moved to this area, finding skilled tradesmen is difficult...


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RE: Kerdi Shower

I'm noticing that the tile guys tend to use cement board behind the Kerdi installation even though it's not required. Can you provide some pros and cons of using different wall surface materials under Kerdi?

Thanks,
Joe


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RE: Kerdi Shower

Mongo...if you are going to go to Philly to install Qdognj's Kerdi shower, you MUST come to CA first...who wants to spend winter in PA when can come out to the sunshine...besides,we'll even have your beverage of choice just like in your tutorial!!! Seriously, would you ever consider coming out here to do my shower for me? Winter time here is truly glorious, hence the insane property values...Rachel


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RE: Kerdi Shower

I'm noticing that the tile guys tend to use cement board behind the Kerdi installation even though it's not required. Can you provide some pros and cons of using different wall surface materials under Kerdi?

Schluter will warranty their system over sheetrock. That's not good enough for me. This system is still relatively new, and there's an issue that makes me a little nervous about the longevity of the system over sheetrock. I'm not worried that moisture will penetrate the membrane. However, think about this-- you've got a nice warm shower on one side of the membrane, and you've got a cool void in the wall on the other side. This is going to cause condensation on the cool side of the memrbane, which is smack-dab up against the sheetrock. Now, I don't think this is going to cause a problem within a couple of years, or even 5 or 6 years. But I'm afraid that over time, it WILL cause a problem with rotting the sheetrock. Using cement board, you completely eliminate this problem, or even the potential for it.


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RE: Kerdi Shower

Sounds like it's time for a road trip!

Mongo


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RE: Kerdi Shower

Thanks, Bill. I figured it would be better to avoid drywall exactly for the reason you mentioned. Would hardi-backer suffice, or is true cement board the right way to go?


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RE: Kerdi Shower

Hardi will do just fine.


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RE: Kerdi Shower

Mongo...just let me know when you've had enough snow, and California is awaiting your arrival!!! Rachel


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RE: Kerdi Shower

This is so cool. Thank you for the info and pics. Can I use Kerdi around my soon to be installed new shower/tub combo? If so, how do I deal with the joint between the wall and tub?


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hey Mongo-- I'll be down in your neighborhood a week from tomorrow-- my brothers and sisters got me tickets to go see Larry the Cable Guy at the Mohegan Sun for my 50th birthday. :-)

Can I use Kerdi around my soon to be installed new shower/tub combo?

Absoultey. As for the joint between the Kerdi and the tub, They have their own caulking-like material called "Kerdi-fix". That'll seal it up.


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RE: Kerdi Shower

Thanks Bill. That's the answer I was hoping for.


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RE: Kerdi Shower

Can I use Kerdi around my soon to be installed new shower/tub combo?

Absoultey. As for the joint between the Kerdi and the tub, They have their own caulking-like material called "Kerdi-fix". That'll seal it up.

Bill or Mongo, do you know if Schluter or anyone else has a picture/tutorial on the whole tub/wall caulking thing? We have thought about using Kerdi in the basement tub/shower combo, but really didn't know how to do it. Do you "caulk" the Kerdi to the tub flange? Does the backer board still go over the flange? Do you still leave a gap at the bottom of the backer board? If so, do you attach the kerdi to the tub or just the backerboard and then caulk the gap?

I just need to be walked thru this with baby steps.

Always ;-)
Hunzi


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RE: Kerdi Shower

Happy 50th Bill !

salbwil


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RE: Kerdi Shower

Thanks, Sally. :-)

Do you "caulk" the Kerdi to the tub flange?

You basically caulk it to the tub's edge (the flat part between the flange and tub itself).

Does the backer board still go over the flange?

You stop it right at the top of the flange, otherwise it'll kick out the bottom of your wall.

Do you still leave a gap at the bottom of the backer board?

Asked and answered

If so, do you attach the kerdi to the tub or just the backerboard and then caulk the gap?

Caulk the gap with Kerdifix, and make sure it's bonded to the bottom of the Kerdi.


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RE: Kerdi Shower

Just like with a great novel, every time I read this I see something new I missed the time before. So you put underfloor radiant heating under the shower tile? Just really really too much, which is just enough :)


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RE: Kerdi Shower

This is going to cause condensation on the cool side of the memrbane,

Could this condensation be conducive to the formation of mold regardless of whether its sheetrock or concrete board?

Bill, what day is the big 50?


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RE: Kerdi Shower

Last month-- october 5th. :-)

Could this condensation be conducive to the formation of mold regardless of whether its sheetrock or concrete board?

No, because it's just moisture in the air. Humidity, if you will. With cement board, it'll just evaporate right back into the air. With sheetrock, I'm afraid that over time, it would deteriorate the gypsum in the sheetrock.

Think about it this way-- in the middle of the summer, you have two cups of ice tea. One is in a glass, the other in a paper cup (think Burger King or Mickeyd's). With both, condensation is going to form on the outside, but which do you think will last longest? The condensation won't hurt the glass at all, but given enough time, the paper cup's going to be trash. Same same.


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RE: Kerdi Shower

"The condensation won't hurt the glass at all, but given enough time, the paper cup's going to be trash."

Aw C'mon Bill, in honor of AlGore winning the Nobel Prize, you really should recycle the cup, not trash it.

Oh, and happy birthday you old man!

Mongo


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RE: Kerdi Shower

Aw C'mon Bill, in honor of AlGore winning the Nobel Prize, you really should recycle the cup, not trash it.

Hey JG-- should I address this? :-)


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also

Thanks, Mongo. :-)

I think. I can't remember. What were we talking about?


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RE: Kerdi Shower

Nice job! On the shower and the posts.

I had my tile guy do his first Kerdi job recently. He watched the Kerdi video several times. You're more thorough!

While I would recommend the system to a homeowner doing a reno or a custom home I still can't justify the cost on a spec home.


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RE: Kerdi Shower

It depends on the level spec home you're building. Obviously, in an 1100 foot spec ranch, you're probably not even going to use a tile pan for the shower. But if you start getting into some of the higher end homes, where prospective owners expect a little more for the big money they're paying, it's always nice to be able to tell them that they have literally the latest and the best system in use-- that it's 100% completely waterproof, which most showers, even high end showers, AREN'T.

Moisture is a home's worst enemy. It'll do more irreversable damage than any other problem your home could have, and the more you can isolate moisture from the structure of that home, the longer it's going to last, and the better off you're going to be. You can very easily make the jump to the Kerdi system actually adding value to the home, due to increased longevity.


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RE: Kerdi Shower

Back on topic.

Had a few people ask what the square piece of Kerdi at the bottom of the wall to the right of the drywall bucket is for.

It's a patch. I had my level leaning against the wall and it got a bit tippy. The corner of the level dinged the Kerdi, so just to make sure I added a 5" square patch over the ding. Remember, Kerdi needs a 2" overlap at all seams, so a 5" patch fulfills that need.

Mongo


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RE: Kerdi Shower

Go for it, Bill! :-) And happy belated birthday to you!


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RE: Kerdi Shower

Mongo,
I'm kind of a "paint"-geek, but after watching this "tutorial" I feel like a "tile-geek"!!

I don't think I've EVER learned so much from 10 minutes on a thread!!! You time & skills to do this are amazing! Also, yours & Bill's insights on all the behind-the-scenes thoughts were very insightfull too.

What's the Kerdi-membrane made of???

Faron


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RE: Kerdi Shower

Faron,

Kerdi is made up of a sheet of polyethylene plastic. On each side of the sheet is a coating of what is referred to as "fleece".

The fleece is actually a fine strand that is spun onto the face of the sheet, it gives it a bit of texture, enough for thinset to bond to.

Thanks for the kind words and I'm glad you enjoyed the thread.

Mongo


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RE: Kerdi Shower

Going through it *yet* again, I have a question: so for the buildup of layers in the corners, did you just compensate for it in overall thinset thickness? If I'm reading right, you *didn't* use the Kerdi-band, you used the regular membrane, so three layers in the corners is going to be thicker than one in the field. Just a matter of thinset height, then?

Thanks.


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RE: Kerdi Shower

Flyleft,

For the most part, yes.

It's not something you really have to suffer angst over, especially with the roughly 4" tiles that I used on this floor.

So "yes", more thinset may end up under one tile and less under another, but it just sort of happens as you work your way across the floor and blend the edges of the perimeter tiles with the inner field tiles to prevent lippage.

Honestly, when dealing with one or two additional thicknesses, I can say for the most part that I comb the thinset out with a 1/4" square notched trowel, and instead of compensating with more thinset under one tile than is under its neighbor, it's more like one tile may get pressed down into the thinset more than it's neighbor, which may result in a little extra squeezeout in the grout lines.

So do I worry about it? No, but it is on my mind.

Now if using small mosaics on the floor, then yes, I'd be much more careful. Larger tiles will span the miniscule differences in floor height while smaller mosaics may ride the wave of the slightly undulating floor.

So again...it's something I'm aware of, but it's not something that I worry over, especially since these built up areas are around the perimeter of the shower floor, and slightly higher there means better drainage. (gotta always look on the bright side)

If you are truly anal and didn't want to compensate for the miniscule built-up Kerdi while tiling, then you could feather in a coating of thinset over the lapped areas, using as small a thickness as possible and feathering it out to nothing. That would give you a smooth starting point if tiling with small mosaic and you were worried about the height differential telegraphing through.

Mongo


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RE: Kerdi Shower

Do you "caulk" the Kerdi to the tub flange?

You basically caulk it to the tub's edge (the flat part between the flange and tub itself).

Does the backer board still go over the flange?

You stop it right at the top of the flange, otherwise it'll kick out the bottom of your wall.

Do you still leave a gap at the bottom of the backer board?

Asked and answered

If so, do you attach the kerdi to the tub or just the backerboard and then caulk the gap?

Caulk the gap with Kerdifix, and make sure it's bonded to the bottom of the Kerdi.


Hmmm....so, behind the tiles that are installed over the tub flange, there's no CBU, just Kerdifix, Kerdi, and thinset. Is that right?

I'm envisioning an installed tub with installed CBU beginning at the top of the tub's flange. Then, Kerdifix on the tub flange and in the tub/CBU gap and thin-set trowelled on the CBU. Then, a sheet of Kerdi set into this Kerdifix and thin-set, so it runs from the tub edge to the ceiling. Later, the Kerdi is trowelled with thin-set and the tiles installed.

Thanks Bill and inspirational tutorial Mongo!


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RE: Kerdi Shower

Hmmm....so, behind the tiles that are installed over the tub flange, there's no CBU, just Kerdifix, Kerdi, and thinset. Is that right?

Exactly.

I'm envisioning an installed tub with installed CBU beginning at the top of the tub's flange. Then, Kerdifix on the tub flange and in the tub/CBU gap and thin-set trowelled on the CBU. Then, a sheet of Kerdi set into this Kerdifix and thin-set, so it runs from the tub edge to the ceiling. Later, the Kerdi is trowelled with thin-set and the tiles installed.

That's pretty much it. The end result you want to have is a flat wall, from tub to ceiling, with a continuous membrane, sealed to the tub, completely covered by the tile, grout, and caulking.


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RE: Kerdi Shower

Thanks Bill for responding. I guess I was having trouble with the 'thin-set-the-tile-to-the-tub' concept.


Does the backer board still go over the flange?

You stop it right at the top of the flange, otherwise it'll kick out the bottom of your wall


So, in a situation where the joists have been extended/shimmed flush with the tub flange, the base of the backerboard should be positioned just above the tub edge (leaving a 1/4" gap) and the base of the Kerdi membrane would be... Kerdi-fixed to the tub edge?...or thin-setted to the backerboard? And the final tub/tile gap is chalked with silicon?


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RE: Kerdi Shower

the base of the Kerdi membrane would be... Kerdi-fixed to the tub edge?...or thin-setted to the backerboard?

How about both! You want to make sure the Kerdi is thinsetted well to the backerboard, and then use Kerdi-Fix to seal the gap between the Kerdi and the tub.

And the final tub/tile gap is chalked with silicon?

I prefer to use siliconized latex caulk, made by the same manufacturer as the grout, so that it'll match the grout almost exactly.


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RE: Kerdi Shower

bill vincent said: "It depends on the level spec home you're building."

I build what is now called "entry level" luxury on an infill basis--$1.5-$2 million. If I were to include Kerdi in the usual 5-7 baths, the buyers could care less; and I'd be out a few thousand dollars that could be more profitably spent. And I'd also be the exception amongst infill builders. Gloss and glitter is what counts.

But I do love reading about "best practices"! And once in a rare while I get a custom job where the client cares too.


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RE: Kerdi Shower

You might be out another 1000.00 on a house like that. Keep in mind, that with this system, the drain comes with it, so part of the cost is offset by the fact that you don't have to buy another drain. In addition, you also don't have to buy or install the Chloroloy shower pan, which will ALSO offset some of the cost.

One other thing to think about-- this system is making a big name for itself. Go into any forum on the web where tile is talked about, especially bathroom tile, and you're guaranteed to see someone talking about this system. It's that good. And for you to be able to tell prospective buyers that the showers are Kerdi, that will show a buyer who's done their research that you're trying to give them a much better quality home than Joe Schmoe Builders down the street. Yes, they want glitz and bling. They also want it to last, and people getting into homes in that price range will have already owned another home, and had to deal with substandard garbage at some point. If you can show them in black and white (rather than just your word) that they're getting much better value for their dollar, you can only help your reputation (as well as the time the house sits on the market). Don't get defensive-- that's not to say you don't have a good rep now. It's just to say you could make it that much better, and that in itself is priceless.


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RE: Kerdi Shower

mongo, thanks for the info on evening out the levels. I remember when I was auditioning tilesetters (I ended up giving up on Kerdi--no one knew about it out here), I showed them the video at the Schluter website and at least two of them said "but there are different heights" and used that as a reason that it was a low-quality installation method another silly housewife was trying to force on them. Yeah, right--they'll believe it when they hear it from a source they respect...I felt like "Hear me now, believe me later" :)


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RE: Kerdi Shower

Fly-- you're in the Seattle, area, correct?


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RE: Kerdi Shower

worthy,

You bring up a good point. Essentially, to me Kerdi definitely is a "substance over style" sort of thing.

I'm pretty much uncompromising on the houses that I build. Fortunately, I'm not a spec home guy, I build 3-4 custom homes a year.

I dictate how the houses are built. The owners, or their designated designers, can dictate how they are decorated.

I don't compromise in the thermal envelope (air sealing, windows, and insulation) of the house. I always do radiant heat. A few other things as well.

I definitely appreciate and understand your statement, because bottom-line customers like that can really drive good building methods down the drain.

I give a 10-year warranty on my homes. And I have to write that I'm rather proud that I can do that.

Best, Mongo


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touring

Flyleft,

Here's your chance to be the left-coast trend-setter!

Only for you, Dear...for your next bath, you and hubby can ring me up, I'll fly to the left coast for a Kerdi-fest.

All I ask for is unlimited good coffee and one free day to browse and get lost in Powell's.

Okay, I'll want to tour your local micro-breweries as well. So you might want to have a first-aid kit on hand as well.

Mongo


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purdy kurdy pikcha

I can't tell who is asking and who is answering anymore, so for whoever was asking, I hope this drawing helps more than it confuses:
Photo Sharing and Video Hosting at Photobucket

Mongo


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RE: Kerdi Shower

hey mongo...this isn't fair! you have offered to fly to seattle when my bath remodel needs you, too!!! what about that road trip you mentioned? we have great coffee in the s.f.bay area, a microbrewery within 5 min. from my house, and we can also offer drop off and pick up services for wherever you want to get lost...hell, we even have two poodles...what more could you want??? rachel


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RE: Kerdi Shower

An afternoon with a couple of poodles...or an afternoon at Powell's Book Store.

Hmmmm...

Ooh, but wait...San Francisco? Home of The Stinking Rose restaurant? Oh yeah, so maybe not the greatest or most garlic laden food on planet earth...but I do have fond memories of that restaurant and I do need to go back.

I now find myself humming Cal-i-for-nia here I come...

Mongo


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RE: Kerdi Shower

keep hummin' mongo, and pick yer date! rachel


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RE: Kerdi Shower

Hey Mongo, Philly is MUCH closer..I'll take you for THE BEST Philly cheesesteaks,if you like, we can make a visit to Atlantic City, throw some craps...There are a couple of nice hotels nearby, i'll put you up there...


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RE: Kerdi Shower

OY, I'm *aching* here...have no idea when we'll be doing another bath project like this one--*sure* could have benefited from your involvement on the project that's just over! But you're welcome to come out anytime anyway--there are lots of great PNW restaurants we need an excuse to go to :) Our home is nowhere near the quality of those you describe building. LUCKY homeowners who have you build their homes/fortresses. That's building for the ages, not just 10 years.

And Bill, we're in Portland...I had tried contacting--is it trask? who's in Astoria?--But he doesn't come into town often, evidently, and didn't know anyone around here. There was one person who replied to my request over on JBForum for a Kerdi person in the Portland area--he said he'd never heard of Kerdi, and was just getting started, but he'd be willing to try...decided to go with a person who was more experienced and did non-Kerdi instead.


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RE: Kerdi Shower

Oh well-- wrong Portland. :-) I don't know why I thought you were in the Seattle area. That's where Shaughnn is.


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RE: Kerdi Shower

Mongo, you rock!

Thanks for the Kerdi tub drawing.

If you or Bill would like to visit the Big O! (Omaha)sometime, we'd be happy to give you the grand tour! Why visit those pesty coastal cities? Come to the Midwest! ;-)

Always ;-)
Hunzi


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RE: Kerdi Shower

hunzi-- how close are you to Hastings?


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RE: Kerdi Shower

Bill,

We're about 160 miles from Hastings. Just a hop, skip & a jump in terms of Nebraska mileage.

Always ;-)
Hunzi


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RE: Kerdi Shower

The reason I asked is I know a top notch installer in Hastings who's very familiar with Kerdi. He even pops in here from time to time. A guy named Bud Cline.


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RE: Kerdi Shower

Mongo, a followup question to the drawing of the kerdi over a tub flange: tub flanges aren't all that thick, and yet it seems that the cementboard is about as wide as it is...? Do you recommend using 1/4" board on tub walls or the 1/2" (what we have in our shower)? If it's 1/2", and even to a certain extent if it's 1/4", there should be some overlap of the backerboard compared to the depth of the flange, yes? Am I imagining this right? There's actual space behind the Kerdi--a somewhat substantial amount of space that I guess would be taken up with the Kerdi-Fix? Does Kerdi-Fix flex at all?

Thanks for any clearing-up you can offer on this...we're thinking now, in large part because of your tutorial here, that we're going to use Kerdi to tile over the wall above the tub in DD's bathroom when we replace the tub, and I want to be *rock solid* (except in changes of plane, of course :)) on my vision of the technique.


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RE: Kerdi Shower

First, over framing, if using cement board then use 1/2" cement board. I feel 1/4" is too flimsy, not stiff enough.

My previous drawing...as is my following drawing...is not to scale. Yes, the flange may be thinner than depicted. Or stubbier.

If using large enough tile, you can install per my previous drawing, with the upper portion of the tile adhered to the Kerdi and the bottom portion of the tile bridging the gap in front of the tub flange.

For smaller tiles, or should you simply want better backing behind the tile, see the following drawing.

In it, a furring strip slightly thicker than the flange is nailed to framing stud. The cement board then gets screwed to the furring strip, with the bottom of the CB overhanging the flange.

Kerdi the cement board, run a bead of Kerdi fix, then embed the Kerdi into the KF. KF is essentially Schluter's proprietary adhesive/caulk for Kerdi. Yes, it's somewhat flexible.

Then tile and caulk the tile to the tub.

In my first picture, you could fill the gap behind the tile with mortar...but without it really having anything decent to stick to, and with the possibility of the flange flexing, I could see that chunk of fill coming loose over time.

Much does depend on the tub and the specific installation.

Anyhow, here's the second drawing showing the furring strip:

And to throw one more bit of confusion into the mix, you can use backer rod (not shown in the drawing) in the gap between the tile and the tub, then caulk. The backer rod is sort of like "foam rope" that can be compressed into the gap, it provides a back wall in the gap between the tile and the tub so you're not trying to fill huge deep crevasse with caulk. Backer rod isn't always required, but I thought I'd mention it.

Mongo


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RE: Kerdi Shower

Mongo, mongo, mongo...

Thank you *so* much for your detailed reply and extra drawing. With something that gives me as much trepidation as tiling (esp. wet areas) does, I do tend to get deep into the details of as many possibilities as I can think of and until I do, I don't feel I have a decent grasp of the reality of whatever the trepidation-inducing subject is.

I realize that not all tub flanges are the same thickness--I was thinking specifically of our Maax acrylic tub in the master when I imagined the tile flange etc (I also realize I didn't take pics of how our tile guy did it and I regret that now). Cast iron flanges would be thicker, of course, and require different treatment. I now feel I will be able to handle any possibility that comes up, with confidence and memory of your drawings and instructions.

Seriously, this is practically a book you've created here, an *extremely* helpful compilation of step-by-step photographs and descriptions that take us all the way through an installation. Just because there's one Kerdi book doesn't mean there can't be another--your work here is so detailed and speaks so clearly to me (more clearly than other books) I can't imagine I'm the only person who would purchase this one in addition to any other ones...a document like this should not be allowed to disappear into the aether as it scrolls off the board...


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RE: Kerdi Shower

thank you so much Mongo for all of these details!! I agree that it is more helpful than the e-book available on another site.

I am a new homeowner in columbus OH and am expanding my master bath into what used to be the laundry room. I plan to put in a 42x42 shower in an alcove. It is a 11-year-old lower-price-range single family home, so I don't want/need to go excessive with glitz, but I want it to be a quality result that will last a long time and look good along the way. I was planning to use a pre-fab acrylic unit (Maax) but the price puts it up with what a tile shower would cost, especially with a friend who knows about these things and is willing to help with labor, so I am trying to figure out the feasibility of doing a Kerdi shower.

1. i am considering getting a pre-made pan, maybe swanstone, and carving out the studs so the backer board will meet the tile flange, sort of how you guys described the tub above. I'm thinking this would still be a quality option and give me a lighter challenge for my first large remodel project.

any thoughts on this?

2. my friend (a superintendent on commercial jobs, 25+ years experience in different positions, general tile experience) doesn't know about Kerdi/Ditra and hasn't read up on it yet. He is open to using Ditra on my ceramic tile floor, but is more confused about the kerdi shower.

he said all he has ever known has been modified thin set on the walls of a shower/wet area, and epoxy grout throughout.

I would like to use 4x4 or 6x6 ceramic, perhaps with a row of 3x6 glass tile as an accent.

I read elsewhere that VersaBond is a modified thinset that could be used on walls with Kerdi when using glass tiles or larger ceramic tiles, but that in general unmodified is preferred.

do you have opinions on this?

also, I have not seen anything specific about the type of grout used - does it still require epoxy grout?

thanks in advance,
lisa


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RE: Kerdi Shower

lisa, a couple of ideas...

With your friend being in commercial, epoxy grout is quite common in commercial. As a matter of fact, it's just about the norm. Epoxy is somewhat overkill for residential, but you can still use it IF you have an installer well versed in its application. User-friendly epoxies, like Spectralok, have gained in residential. But in residential, plain ole portland cement based grout still has the lead.

Thinsets. Yes, a transition in ideology has to be made here as well. Prior to Kerdi or other thinsetted air-impermeable membranes, modified thinsets were the best. Better bonding, better performance all around.

Modified thinsets, however, need air to fully cure. the portland cement based part of the thinset cures via a chemical hydration reaction. No air required.

The acrylic modifier, however, needs air to cure.

Put a dollop of unmodofied thinset in a ziplock bag and it will harden.

Put a dollop of highly modified thinset (Flexbond, for example) in the same and days later it may still be slightly mushy. No air means a delayed cure.

Were you to use a highly modified thinset like Flexbond when attaching large 18" porcelain tiles to Kerdi, the thinset around the edges of the tile may cure, as air can access the thinset through the unfilled grout joints. The thinset towards the center of the tile may remain soft for quite a while.

Uncured thinset behind wall tile may result in the wall tiles sagging over time. On a floor, walking on the tiles may cause the tile to shift, breaking what little bond that had already formed between the tile and the substrate.

Were you to do the same with small 2" square mosaic tiles, there are more unfilled grout lines to allow better access to free air, so the modified thinset should cure more quickly.

So where does this lead?

Schluter has fairly specific ideas on what type of thinset (modified or unmodified) to use to bond Kerdi or Ditra to different substrates.

They also have guidance on what type of thinset to use to bond tile or stone to Kerdi or Ditra.

There is a middle ground. Sort of. It's slightly endorsed by Schluter's technical staff, and fully endorsed by tile setters familiar with the materials.

I've had no problems using a lightly modified thinset (VersaBond since we're into Custom's line) when tiling over Kerdi or Ditra. That's with small or medium sized tile.

Were I using large format tiles, then I'd use an unmodified thinset.

Now that's me. Others may have other ideas or preferences.

With your 4" and 6" tiles, I'd feel quite comfortable using a lightly modified thinset over Kerdi.

As to grout, I seldom use epoxy grout.

In a Kerdi shower, the only thing that can get wet is the tile, the grout, and the thinset. There is no deep wetting in the lower layers that make up a "typical deck mud" shower pan. With superficial wetting you get quicker drying and less chance of dirty grout.

Just have a properly pitched floor and proper ventilation in the shower and all should be well. You can still use an epoxy grout should you want, though, it's fully compatible with Kerdi/Ditra. Just give modified thinset plenty of time to fully cure prior to using the epoxy.

Regarding "carving out the studs". Yes, you can notch the studs. Just be sure you still have clearance to get the pan into the space and rotate it down to the floor so you can set the flange into the notches. With three wall you should be able to slide it in. Add a fourth wall, or a framed entry on the fourth wall, and the pan may not fit.

You could build the shower slightly larger and furr the studs on after the pan is set.

Hope this makes sense!

Mongo


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RE: Kerdi Shower

thanks so much mongo for getting back to me so quickly! very clear. i will pass this on to my friend and see if he has any other questions.

thanks,
lisa


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RE: Kerdi Shower

hi Mongo (or anybody with an opinion :) - my friend wanted to know your opinion on this: if we use regular grout, how might the constant wetting & drying affect the integrity of the grout? Would it start to deteriorate because of this? That seems to be his primary reason behind wanting to deal with all the pain of using epoxy grout... for resilience in such a wet area.

thanks again,
Lisa


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RE: Kerdi Shower

I've never had a grout failure. Even in heavily used steam rooms where the grout has a higher chance of becoming saturated by driven steam versus a more topical wetting from water in a shower.

Most of the problems I've read about on this forum and dealt with in occasional arbitration-type cases where I've been brought in as "the decider", the grout problems are usually caused by the installer.

Too much water in the mix, too much water when cleaning up. Usually water or water-quality related. Dumbest ever? A beach house. No running water on the property, so the guy used buckets of ocean water to mix the thinset and grout. Anyhow...

You can use epoxy or Spectralok over Kerdi. Some feel more secure with epoxy.

So don't let me shy you away from it. Just give the thinset a couple of days to fully cure prior to grouting with epoxy.

Mongo


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RE: Kerdi Shower

So mongo - what part of CT are you in? I need a kerdi shower (among other tile stuff) done. I am in NY but not too far from CT border (depending on where you are of course.)


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RE: Kerdi Shower

I'm about halfway between New Haven and New London, if you're familiar with the small towns I'm near Old Saybrook/Old Lyme. Near the mouth of the CT River.

Typical traffic, about 80-90 minutes from the CT/NY state line.


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RE: Kerdi Shower

hi Mongo - I have started thinking about this project in more detail and am not sure how to deal with the part where the valves are meeting the kerdi. can you give me a few details/pointers on that? I will only have 1 valve assembly that will control the water and have a diverter to the regular shower head & a rain one we are putting through the ceiling (not tiled). I believe the entire valve assembly will be sticking through the cement board, then covered with the trim (Moen). what do i do with that area as far as kerdi goes?

also, i plan to mount my traditional shower head high on the wall (8 foot ceilings, likely mount it at 7 feet or so) - how close do i need to get to that with the kerdi & tile?

thanks
lisa

p.s. - do you & bill have a donation/tip/appreciation system set up at all? I have already learned so much from both of you, and will probably ask a bunch of questions as we go through this, and it would be nice to have a way to thank you in addition to my words here :)


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RE: Kerdi Shower

Too far. :/ You'd spend half the day in your car. Oh well.


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RE: Kerdi Shower

"I believe the entire valve assembly will be sticking through the cement board, then covered with the trim (Moen). what do i do with that area as far as kerdi goes?"

There are two ways to deal with penetrations through the kerdi:

1) For a 1/2" (pick a size, any size!) tubing penetration, punch a 1/2" diameter hole through the Kerdi. You can use the sharpened end of a piece of scrap tubing to punch the hole through, or you can mark the location and cut it with utility knife/scissors. The tubing runs through that hole, then use Kerdi Fix (sort of like a caulk) to seal the Kerdi to the tubing. That's what you'd want to do in a steam shower, or where you want zero perforations in the vapor barrier.

2) Treat it like a regular "non-sealed" shower. This is standard in most showers. Cut a slightly oversized hole in the Kerdi so you have access to the valve stem and any adjustment screws (temp setting limiter, etc). Then tile, with the tile not blocking those same screws, etc. The escutcheon plate for the valve will cover the oversized hole, making it all look purdy. The cover usually has a foam gasket material running around the circumference of the plate, that foam (with the exception of an open spot at 6'oclock on the escutcheon plate) seals the escutcheon to the tile so no water can get between the escutcheon plate and the tile. The non-sealed part at 6 o'clock is your "just in case" space. It allows water to drain out just in case water were to get behind the plate.

"also, i plan to mount my traditional shower head high on the wall (8 foot ceilings, likely mount it at 7 feet or so) - how close do i need to get to that with the kerdi & tile?"

While you have minimum code heights (72") that you need to tile to, I usually tile to the ceiling and tile the ceiling as well. If not going to the ceiling, then it's a matter of preference, depending on the tile design you've chosen. I do prefer the shower arm to come through tile.

"p.s. - do you & bill have a donation/tip/appreciation system set up at all? "

You might want to ask Bill. He had a setup last year for donations to provide bulletproof vests for police dogs. Not sure if he still has that going. Me? No, just pass along a bit of goodwill to the next person you meet.

Mongo


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RE: Kerdi Shower

This is strictly voluntary. You can donate if you like, and if you do the amount is strictly up to you. Any and all donations are very much appreciated by the dogs and police departments that receive the vests.

Here is a link that might be useful: Vest N PDP


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RE: Kerdi Shower

thanks, bill, for chiming in - i'll definitely pass some cash on to them, and "pay it forward" in other ways too


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RE: Kerdi Shower

Thank you very much. You'll never know just how many "ripples" you're sending out across "the pond". :-)


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RE: Kerdi Shower

Thanks so much for this post. We're planning to use Kerdi and the diagrams and pictures were very helpful. This post should stay at the top and alive for anyone considering Kerdi.


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RE: Kerdi Shower

Mongo and Bill - I only wish that every tile installer had half the integrity and concern as you two. I would love to have either of you install tile in my home any time! Only problem is that I live in the Nashville Tn area! Mongo you are so correct when you say that moisture is a home's biggest problem. My DH and I have spent almost $20,000 fixing water damage on our home in just the last 2.5 years alone. Just last year, we replaced a 12 year old tile shower because it had leaked (for the 2nd time) and rotted out part of the subfloor. (You may remember me posting for tile floor help last spring). That job ended up costing us 10k and we decided to go with a cultured marble pan and shower surround because we were too paranoid to go with tile again, even though it is beautiful. (This is on the 2nd floor, as well). There is green board behind the cultured marble but my understanding is that's fine since it's not behind tile. We have no grout lines, only caulked seams where the marble walls come together and all around the top of the shower pan, which is solid. So, we hope we're good for a long, long, time. Neither of us can bear to go through this water damage mess again. I won't swear off tile showers but if I ever had one I would want one of you two guys to install it - with Kerdi of course! Amy


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RE: Kerdi Shower

joynserf, you;re welcome!

Amy, once a person is bitten by the $$$ of repairing water infiltration, it's often the tile that gets the blame instead of the tiler who did the crappy installation.

May your 2008 be a dry one!

Best to both of you,
Mongo


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RE: Kerdi Shower

Oh, I definitely know that it wasn't the tile's fault, but rather the tiler. Tile is beautiful but if it isn't put in correctly, it can literally ruin your house! I may have it again one day but only in a downstairs bathroom and only with Kerdi behind it! If you know of any "great" tilers in the Nashville area, please let me know. That would be a valuable resource to have. Thanks! Amy


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RE: Kerdi Shower

This is extremely interesting about Kerdi. I am so sick of fighting (and losing the battle) with mold, we were dead set against tile for our new house. Now to convince my husband.

Micro breweries? Gee Mongo, then perhaps I can coerce you into coming to the north Georgia mountians to Kerdi my shower. I have a state of the art home brewery and have won many an award for my beer. Of course, with home building starting this summer I don't expect to be firing up my system.


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RE: Kerdi Shower

I'll be in ATL from mid-Feb to mid-March. I get thirsty when in ATL!

If you're into north Georgia brewing, do you know or have you heard of Phil Farrell? He's a buddy of mine from the Air Force, we were in the same fighter squadron years ago.

Mongo


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RE: Kerdi Shower

LOL! Phil's in my brew club! Makes some FINE beer and has won way more ribbons than I! Oh, and came in second as Beerdrinker of the Year last year.

Jodie


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RE: Kerdi Shower

If you see him, tell him "Mongo from the Green Demons" said howdy!


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RE: Kerdi Shower

Will do!


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RE: Kerdi Shower

HI all, thanks so much for the explanations, I'm totally convinced we need to ask for the Kerdi in the new house build. A few months ago it looked like Flyleft researched this, does anyone have a recommended installer in Portland Oregon (or someone who wants to travel)? Microbrews and/or good coffee and muffins optional.
Thanks!
susan


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RE: Kerdi Shower

Bump


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RE: Kerdi Shower

First, credit for this photo goes to Joe, it was originally posted by him on his thread. On his thread I used MS Paint to "illustrate it" a bit, I'm going to repost the picture here due to the large number of emails I've gotten over the past few days regarding the drain. Hopefully this will consolodate things a bit...so the following is a sort of cut and paste from his thread:

The drain ring and the drain cylinder are two separate pieces that connect together. The fingers on the ring grip the cylinder, so you can slide the ring up and down the cylinder and that sliding up and down action allows you to adjust the height of the square metal drain cap.

In Joe's picture, the Kerdi flange has already been installed and it's covered with Kerdi. The depression that the gray drain ring is sitting in is part of the already installed flange.

Looking at the picture, if you pressed down on the square metal plate, the cylinder would slide downwards through the ring. You'll do that to set the top of the metal plate flush with the top surface of your floor tile.

Again, if Joe's floor were tiled up to the drain, when it's time to set the drain I would:

1) Remove the gray drain assembly, which when all snapped together includes the gray ring, the gray cylinder and the square metal plate.

2) lay a ring of thinset around the open drain hole, in the "depression" of the Kerdi flange.

3) Place the gray drain assembly back in the drain flange, pushing it into the ring of thinset. Thinset will ooze through the holes in that gray ring.

4) If needed, at this time a little more thinset can be placed on TOP of that gray ring, right up against the gray cylinder, between the ring and the square metal plate. You won't need much.

5) Now push down on the metal plate, gently. The pressure will force the cylinder down through the gray ring, causing the height of the metal plate to go lower. Keep pressing until the top of the metal plate is flush, or just slightly below, the height of the adjacent tiles. This may cause some thinset to squeeze out, that's desired, as it means you have complete thinset coverage and support underneath the square metal plate.

You want to think of setting the square metal plate as if it were just another piece of tile. Thinset under it, push it down in place so it's the same height as the neighboring tiles, and clean up and squeeze out.

Mongo


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RE: Kerdi Shower

Mongo,

Many thanks for all your hard work! I don't want this to disappear before we get to our shower so...

*bump*

cintijen


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RE: Kerdi Shower

Mongo,
A little advice if you please.
I have been attempting to do a tub surround with Kerdi/band/fix and when I peel back the Kerdi to check thinset coverage I see lots of trowel marks. No amount of smoothing with my drywall knife seems to help. I was forced to peel off a sheet of Kerdi and discard it. Pricey. My thinset mix is "fluid" as they recommend, like cake batter. I am using hardi for the backer. I misted the walls prior to beginning, though I notice the hardie soaks up the water quickly. Any suggestions would be most appreciated.
Thanks,
ggoose
p.s. Did I read in one of these posts you were in a "squadron"? If so, which?


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RE: Kerdi Shower

Thanks so much for this post and all of the useful information. However, I'm thinking it would just be best if you'd come and do our shower, please please!!!


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RE: Kerdi Shower

ggoose-- let me ask you-- when you went to peel off that piece of Kerdi you threw out-- did it come off easily?


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RE: Kerdi Shower

Hello Bill,
The thinset hadn't set completely, so it came off easily. After repeated attemps to properly seat it, and pulling a corner back to check, and still seeing trowel marks where ther was no thinset, I pulled it off while still damp so as to try another day. I read on another thread the hardi must be sponged down, as it is very thirst. Also, the writer of the other thread said to mist the membrane itself. Perhaps that was my problem.
ggoose


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RE: Kerdi Shower

ggoose,

My thinset is thicker than cake batter. Thick enough so it won't self-level if poured in the floor. But thinner than a typical mix.

I apply the thinset to the walls with the flat side of the trowel and work it into the texture of the board, leaving a thin layer on the board, maybe an eighth-inch plus.

I then comb it with the notched side, which removes the excess. If you are troweling with the trowel at too low of an angle against the hardie, you might effectively be taking too much thinset off the board. The lower your angle, the smaller the ridges and the less thinset you leave behind.

If you are troweling at the proper angle, then the notches on your trowel might be too small, or your thinset so loose that there is too much water and not enough solids going on the wall.

What size trowel are you using, and is it "V" or square?

Squadrons? I was in several over the years. Operationally off the top of my head the 356th, 25th, 357th, 358th. Training the only one I remember is the 433rd.

I think most every fighter squadron had a...

Mongo


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RE: Kerdi Shower

Hi Mongo,
I'm using the recommended 3/16 X 1/4 inch V-notch trowel. I think my trowel angle is OK, as I got good adhesion where the hardie wasn't (like over seams that had been reinforced w/mesh and thinset). I just couldn't get the ridges to fill in the troughs in the feild, no matter how much coaxing I did with my drywall knife. I'm beginning to think the hardie drew too much water too fast, and it began to set a bit.

A warthog driver, perhaps?

ggoose


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RE: Kerdi Shower

It could be.

I've installed Kerdi over cement board (wonderboard or durock) 90% of the time, and only on fiber-cement (hardie) occasionally.

You could go to a larger notched trowel and give that a shot. Test it out on a small sample board. You can clean off the Kerdi and reuse it unless the thinset has cured.

Yup, I be a hog driver. How 'bout yourself?

Mongo


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RE: Kerdi Shower

"You can clean off the Kerdi and reuse it unless the thinset has cured."

Wish I knowed that then. Think I'll look for a slightly larger trowell, and maybe warm up with half-sheets instead of full tub-to-ceiling sheets.

Me, just a lowly faip.

ggoose


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RE: Kerdi Shower

I can't speak to using hardiboard, as I use it as little as possible (just a personal preference), but I HAVE heard that it needs to be misted. However, this is the first time I've heard of wetting down the Kerdi. As for consistency, I usually mix mine like loose pancake batter. Mine WON'T hold its shape. As fot trowel size, 3/16x1/4 should be big enough, but if you're having problems, try going to 1/4x1/4, or even 1/4x1/4 v-notch.


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RE: Kerdi Shower

Thanks Bill,
My thinset sounds just a little thicker than that. As I mentioned, on another thread they said sponging the hardi proved effective, so I think I'll try that w/a 1/4 X 1/4 trowel and see what happens. I have 2 bathrooms to do so the next one will be hardi-less. Thanks for thr reply,
ggoose


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RE: Kerdi Shower

No problem. I take it by your "handle" that you're also a military pilot?


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RE: Kerdi Shower

Once upon a time...now I'm just a Kerdi-hangin' wanna-be.


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RE: Kerdi Shower

Where and when did you faip? 37s or 38s? Or whatever they are flying these days? Did you do ATC the entire time in? I did UPT at Reese, 85-02.

And yeah, after reading Bill's question and going back and reading your previous post...do not mist the Kerdi. Mist the hardie, let it absorb the water, then trowel and comb your thinset, then hang the Kerdi.

Then repeat.

Then repeat again and again until everything is orange.

Then you stop, clean the thinset out of your hair, clean your tools, and drink beer.

Mongo


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RE: Kerdi Shower

T-38's at Reese (UPT also, class 87-05). I probably knew some of your faip classmates. Did my faip tour and went to Delta with a 2 yr C-5 stint at Kelly (reserves).

I think I need to "mist" a little more aggressively, as the only reason I can see for the thinset ridges not collapsing behind the kerdi is moisture wicking out too quickly. I'll try again monday. Happy 4th!

ggoose


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RE: Kerdi Shower

The first time I mist the board I wet it good, going over it twice, to the point where water is running down the face.

Then I mix my thinset.

While the thinset is slaking, I mist again.

You do need to work fast, so get the thinset on the wall with the flat side of the trowel, I work floor to ceiling, then comb it with the notched side. Then immediately hand-hang the Kerdi and pat it down with your hands. Then embed it with a trowel or drywall knife.

Hell, if you can survive as a faip you can hang Kerdi!

Spanky Barber (-38 faip) was a classmate of mine. I'm 7ER with the bankrupt widget. Maybe I'll see you on the NAT tracks some day. So we don't thrash the thread with off-topic chatter, email me off my "MongoCT" name/link if you want.

Mongo


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RE: Kerdi Shower

I can see my misting was insufficient. I need to saturated the hardi a bit more. I've noticed as I've been hacking away at these first attempts that where there is dry thinset over the hardie the kerdi adheres quite well. I'm guessing it doesn't wick moisture away as quickly. I'm tempted just to skimcoat the hardi with some thinset and be done with the problem.

Good ol' Spanky...hadn't thought about him in a while!

ggoose


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RE: Kerdi Shower

I use wonderboard or durock cement board for most everything. I do find that when cutting this strips, like those needed to line the shelves of a niche, it's easier to use hardie, as the fiber-cement takes screws better than a true cement board like durock or wonderboard. Thin strips of cement boards can fracture easier than fiber-cement when screws are driven through them.

In this photo, I lined the niche with hardie, then skim coated it with thinset before going over it with Kerdi.


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RE: Kerdi Shower

Thank you so much for all the steps and trouble shooting!

Somehow I knew you were either teachers or military men Mondo and Bill!!!

Sent this to Hubby- hopefully he'll see what I am talking about now..........

Thanks Again!
Heather


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RE: Kerdi Shower

Hi Mongo,

The thinset skim coat and heavy "misting" seemed to do the trick, and the kerdi is going up nicely. Thanks for the help. Any chance you might post a picture of the niche in your shower?

ggoose


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RE: Kerdi Shower

Here's a shot of the niche in this thread after it was framed but before the cement board went up. The niche wall was skinned with 3/4" ply before the cement board went up.

Here it is after it was tiled:

Mongo


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RE: Kerdi Shower

WOW.
Most impressive. It is difficult to discern any slope to the shelves in the tiled pic. Was the slope built up with thinset or via the actual framing, pre-cbu?

...maybe you should quit your day job.

ggoose


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RE: Kerdi Shower

Have to admit, I'm nervous as a cat at the dog show about doing my first shower-- I've laid enough floor tile to be comfortable with tile and thinset, but the only vertical I've ever done was a backsplash.

My showers and tub surrounds were done in plain white gyp board by my builder, who is in the hospital, may not get out. I'm tempted to pull it out, replace it with hardi or similar. I know its *supposed* to be OK to go over the whiteboard, but tell me, pros: Would you? Does the fact that I'm in a low-humidity environment matter either way?

I thought I was clear on using only unmodified thinset on kerdi, but their web video says to use something 'appropriate to the substrate'. What would that be, for white gyp board? I don't currently have a 1/4x3/16 v-notch, don't mind buying one if it will be genuinely better than my 1/4x1/4 square: will it?

Has anyone tried the plastic corner mouldings that replace caulked corners?

Dryset is reccomended in the video about installing the tray, but thinset is mentioned in the one about installing the drain flange separately. Which should I use?

I'm worried that I'll go to the site the next morning, and all the wall tile will have fallen off, ruining the schlutter pan. Does it matter which unmodified thinset I use?

It would lift a great load off me if anyone can answer any of these questions-- I'm feeling really stressed...


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RE: Kerdi Shower

ggoose,

The framing is pitched. The way I feel today I'm contemplating quitting ALL my jobs.

Oruboris,

I think you can feel confident going over white board.

Thinset? Over drywall or cement board you can use a lightly modified thinset should you want. Most thinset manufacturers offer unmodified (~$8 a bag), modified (~$15 a bag), and highly modified (~$30 a bag) in their product lines.

the only time I'll absolutely not use a modified thinset with Kerdi or Ditra is when using large format tiles.

Trowel size? Buy the correctly sized one.

I've never used the corner strips. Bill has posted several pictures of jobs he's used them on.

"Dryset is recommended in the video about installing the tray, but thinset is mentioned in the one about installing the drain flange separately. Which should I use?"

"Dryset" is unmodified thinset, so dryset is thinset.

Mongo


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RE: Kerdi Shower

The way I feel today I'm contemplating quitting ALL my jobs.

Been there, done that. :-) Tomorrow's another day, my friend. :-)


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RE: Kerdi Shower

Hopefully it won't be a Bill Murray "Groundhog Day"!


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RE: Kerdi Shower

Thanks for the reassurance-- I *thought* dryset and thinset were the same, but the video used 'thinset' right up to the drain flange install, and that threw me.

I think I was getting overwhelmed by un-assimilated info, and after re-reading parts of this, and re-watching the videos, I'm feeling much better...

Thanks again.


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RE: Kerdi Shower

Is it an acceptable practice to feather out overlaps in the kerdi with thinset as one might do with drywall mud on sheetrock? This, of course, in an effort to help level the tiling plane.
Thanks,

ggoose


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RE: Kerdi Shower

No need. You're only talking about 1/16". Or atleast you SHOULD be. :-)

Has anyone ever checked Kerdi for Radon?

:-)


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RE: Kerdi Shower

Just completed the shower-in-tub-surround-overkill-with-kerdi application. I'm reasonably pleased. However, I'm wondering if I made amistake with the thinset. I was at Lowes and got the unmodified Laticrete product, but now notice the packaging says "Floor Adhesive". Is this acceptable for use to hang kerdi and tile over it? The Lowe's assoc. said it is their only unmodified thinset. Also said I can only use it on the walls to hang 6X6 tiles - no larger. Is this true?
Hoping I didn't go anywhere near the pooch,

ggoose


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RE: Kerdi Shower

For tiling on Kerdi, you have tile larger than 6x6 and want to use unmodified?

If so, then the pooch is safe, Gus.

Do realize for walls you'll want tile spacers to prevent any creep on the walls. Unmodified creeps a bit more than some of the other modified or lightweight thinsets, but unmodified is what you want with Kerdi.

Regular "X" shims are okay for the most part with an occasional micro-tweak as required. Tile spikes (tapered shims) allow a bit more +/- flexibility. For a one-time use, the inexpensive white plastic X's are fine.

Mongo


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RE: Kerdi Shower

I am using mostly 6X6 tiles, with just a few that are larger, on the walls. Have spacers at the ready. Was curious if the Laticrete "Floor Adhesive" thinset is acceptable to use to hang the kerdi and the tiles...that's all the unmodified Lowe's had, so that's what I used (to hang the kerdi), and planned on using to hang the tiles...

ggoose


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RE: Kerdi Shower

I'm not familiar with that particular product so I went on Laticrete's website to view the pdf. Found out it's a "lowe's only" product.

And the sheet does specifically say that it is "not for walls". I'm not sure what the mix is, if it's a little light on portland or what.

Lowes also carries Mapei, did they have any unmodified in their line?

Do you have a Home Depot nearby? They carry Custom's line and they usually have unmodified in stock.


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RE: Kerdi Shower

First, we have to figure a way to keep this thread alive, and preserve as much of the info herein [including replies to questions] after it hits its limit, still 150, IIRC.

Second, question on time: basicly, I have none. Hiring a tile guy to hang the walls, but he hasn't done kerdi before, so I'm supposed to do that before he gets here.

How long should I allow the kerdi to cure before we do tile?

He's a biiig guy, wondering if I should have the floor done before the walls so he doesn't hurt the foam pan by standing on it, or dropping a tile or some such. Good idea, or not necessary?


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RE: Kerdi Shower

oruboris, I saved all the pics separately, and saved the text...this must not die. Nor do I want g'web to appropriate it and sell it as a book...


 o
RE: Kerdi Shower

"Nor do I want g'web to appropriate it and sell it as a book..."

John Bridge already beat them to it. He's using my photos on his updated site.

Someone emailed me a while ago and told about the 150 post execution. No worries. Maybe I'll consolidate and start another thread, maybe have one thread for the photos and one for discussion? Might take a few days for me to get round to it.

And just what is the "gallery". Is it just for photos? Do "gallery" threads die?

Oh, and whoever makes the 150th post to this thread before I remodel and repost will die...

Mongo


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RE: Kerdi Shower

Mongo,

Thanks for the excellent photos and advice.

What angle or pitch would you recommend for shower niche shelves made of marble?

How do you attach the cement board for the back of the niche?

Would you recommend installing a furring strip on a wall framed in 2x3 metal studs when placing 9"x18" tiles horizontally?


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RE: Kerdi Shower

Mongo....That would be me. An EXCELLENT tutorial on Kerdi showers and I figgured that JB Forums would benefit from your expertise.


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RE: Kerdi Shower

We're putting in a custom shower and this can not get lost before we're ready so another giant thank you to Mongo and ... another Bump!
golddust


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RE: Kerdi Shower

Posted by Yumpin Jim1mckenna@yahoo.com

Thnk you for all theinfo great stuff. I am doing Keri for the first time I am confused about the thin set . The tile place I bought from sold me Maipei Karabond Premium Grade Dryset Mortar for the kerdi, North American adhesive Premium ahesive prmix for the tile on the walls. (all of it Not to cheap) they also wanted to sell me another thinset for setting the floor that is 1x1 mosaic tile. not sure if I have the right stuff or not. Can you tel me what I should use. For the job? to set shower Pan,Kerdi,wall tiles witch are 10x13, and floor tiles witch are 1x1 Mosaic. agin thank you muuuch


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RE: Kerdi Shower

Bring back the premixed crap. All you need is the Kerabond for ALL of it-- installing the Kerdi, the wall tile, and the mosaics on the floor.


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RE: Kerdi Shower

Mongo, Unfortunately the pics are no longer part of this thread. Would love to see them as the text is very descriptive and I am working on tub deck shower combo. Do you have a link to the photos? I am located in SE CT and not far from you.


 o Post a Follow-Up

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