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wayne bergman
05-09-2015, 09:18 PM
Great forum here. I have two showers to tile in our home that will be a new construction addition to our home. I have 12x24" Porcelain tiles 3/8" thick for this project. I have the 1/2" kerdi board that I will use for the tile backer board. I will be using unmodified thin set as recomended by Schluter. For the floor of the shower I have gone with a pre built Fibre Glass reinforced shower base so that should make things a littel easier for me but it was expensive. I have tiled a few showers before as a home owner and things have turned out alright but now as I am using the Kerdi Board for the first time I have a few questions......

1. I have had good framers doing on our reno for but the shower studs are far from plumb or fair. I have got out my hand plane to fair things out a bit but I can see I will have a few dips and what not in my kerdi board if I suck the baord into the studs with the kerdi fasteners like is recomended without a lot of work faring out all the studs. I am wondering if its a good idea to just fasten the kerdi board to the studs with either thin set or Kerdi Fix and then after the adheasive is dry I could further fasten the kerdi board with the proper fasteners? This way I could just kind of press the kerdi board into the adheasive with out too much pressure so the board does not conform to the warped studs.

2. Also I want to confirm the notch size that would be best for my wall tile?

Thanks in advance.........wayne

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05-09-2015, 09:55 PM
Hi Wayne,

The method you describe is not specified by Schulter but I've read of various pros on the site using Sikaflex ($6) at Homers or PL3 to attach and square up the Kerdiboard. Not a approved method but it's your home and your shower. I've include a link to the discussion below:


Following up with the screws and washers is up to you. I'd probably skip the washers and just use the stainless screws to keep the Kerdi board in place as I installed the squared up panels.

You can follow up with Kerdi fix over the screws and Kerdi band over the corner and joints

1/2 notch is what I used for that size tile in my master bath.

05-10-2015, 06:25 AM
# 1 yes that would work with thin set, let dry followed with screws / washers and kerdi patch. This method is approved by Schluter.
It would be better to scab or replace warped studs.

Wayne, make sure you have a sturdy pan some of the cheap pans won't hold up.

05-10-2015, 10:05 AM
Welcome, Wayne. :)

I would not recommend you attempt your plan using thinset mortar to bond KerdiBoard to dimension wood studs. I can't imagine Schluter authorizing such a proceedure and if Patrick has such information from Schluter I wish he would post a link to his source.

Even using the thinset mortar as a "shim" between dimension wood and Kerdi Board and then attaching with mechanical fasteners through the mortar would be very questionable to my thinking, but as PC correctly points out, it's your house and your shower and your decision.

My opinion; worth price charged.

05-10-2015, 10:54 AM
I do it all the time Wayne.I use Kerdi fix and just push the board into place and then come back the next day with screws and washers.

05-10-2015, 03:43 PM
The washers are an important component to the fastening system, and I would NOT just use the screws. Using the washer spreads the force out and, allows you to slightly recess the whole thing so that you can cover it with Kerdiband without having a hump there. If you just use the screw, it is way to easy to poke a head-sized hole in the board, and then, there's really very little holding the panel to the wall. The washer allows it to compress a conical depression in the panel and unless you get extreme about it, prevents poking through the surface layer.

Use something like a long level to help embed the panel and keep everything plumb without waviness in the surface. AT the base connection to the pan, you can notch the bottom to fit over the tiling flange - use KerdiFix on that seam when you band it to the pan.

05-10-2015, 05:03 PM
yes, I agree documentation is important. The only documentation that I have at this time is from the Schluter Innovation Workshop Feb. 2014 demonstration by Russel K. Russel said, plumb walls by applying thin set to studs as needed, use your level to plumb, let dry, fasten with screws and washers. Note some studs would get screws and washers as soon as you put your board up.

wayne bergman
05-10-2015, 08:02 PM
Thanks guys for the great feedback and links. What I am leaning towards at this point is to continue to take out the high spots from my studs with my hand plane and then take care of the low spots with healthy fills of PL Premium on the studs so I dont have to fully suck the Kerdi Board into the dips on the stud work. I may spray my screws with pam or something so it does not stick to the PL Premium so after the PL premium hardens I can further torque the screws and washers to dimple my kerdi board for the kerdi band and thin set treatment.

A few questions I still have please......

I have noticed on this forum that the Sikaflex Limestone Construction Sealant is a good replacement for the Kerdi Fix but my local Home Depot did not have it in stock or the Kerdi Fix so I may have to buy my sealant on line. A couple of questions please regarding the sealant to be used with the Kerdi Board. .......

1. I am wondering if anyone knows of a good place to get the Kerdi Fix online from a Canadian supplier. I am in Canada and shipping from the USA can be a bit expensive and slow to cross the border?

2. Am I right in that the Kerdi Fix is just used between the Kerdi Board and the shower base and also to fill in the spaces between the Kerdi Board and the fixture spouts?

3.I guess I would still use a silicone for these same spaces when it comes to sealing the tile at the completion of the project?

Thanks again folks, as the components for this shower build is so expensive I want to make sure I am doing everything right. I will post pictures of the progress as I go. I may not start the shower for a week or two as the drywall crew will be on site next and I may want them all out of the way before I start.

Houston Remodeler
05-10-2015, 08:41 PM

If you use PL to adhere the sheets in some spots, there is no need to come back with screws in those spots later. No torquing needed. Just use a long straight edge to set the kerdi board. In our last installation, we used 1 screw to hold an entire sheet overnight while the PL set. Next day the sheet wasn't moving.

1- Use Sikflex construction adhesive or sealant.

2- You're not using the kerdi seals ? but yes we do the filling when the seals don't fit such as Grohe fixtures.

3- Yes, color matched is a nice touch

05-10-2015, 08:54 PM
Personally, I like the idea of no caulk, and would seriously look into profiles and expansion joints.

wayne bergman
05-11-2015, 09:34 PM
I have a questin regarding the kerdi seals. I was asking my Son what he thought about using these as he is a plumber. My son has done all the nice plumbing on the project so far. I sent him a link to view the details on the kerdi seals and his response was.....
It does look pretty slick,but I'm not 100 percent sold on them for a few reasons. If they are going be a good seal they have to be a very tight fit around the nipple, which means all of the pipe dope will get scraped off when you put your finished shower nipple/trim on. I would rather not have that, and have the pipe dope on the threads going into the wingback in the wall. Also I'm not sure how the sizing of those seals works around the valve, but it would be a shame to have any of that in the way of the integrals around the valve, or block access for finishing time. You would have to see how the trim goes together and make sure it doesn't interfere with integrals of the valve or assembly at finishing time. Because every valve is a little different and Kerdi is selling probably a few sizes only. If you don't think it will interfere and you think it is worth the extra order it might be worth it. I still don't really like the nipple ones, but if you think its a good idea then go for it.

So my Son is thinking about this from a plumbers point of view and wondering if he has a good point?

05-11-2015, 10:21 PM
You could always use tape on the nipples instead of pipe dope...done right, it won't be pushed off. Then, if you figured your length correctly, you could just put the nipple in there before you install the seal. You really need one there when installing it so that it is properly centered, but you could take it out after, if you wanted. Or, you could use a bead of KerdiFix after installing the nipple. Those seals are important if you're using drywall as the backer...not so much with KerdiBoard.

05-12-2015, 09:40 AM
I skipped all the spiffy seals Schluter has available. For the valves and diverters and such, they didn't fit anyway and I was satisfied with what the manufacturer provided with their parts.

For the nipples, in my situation, they are so high up on the wall (shower head height) that they will see no significant water in their lifetime.

If you're still concerned, smear the drywall edges and/or fill the holes in the tile with Kerdi-fix or Sikaflex.

05-12-2015, 10:40 AM
I would have my drop ear almost flush with the outside of the kerdi board and use Kerdi fix to fill the gap.

wayne bergman
05-15-2015, 08:58 AM
Thanks for the tips Jim..... I have a few questions please on your help below as I am not real sure on a few things......

You had mentioned ....."AT the base connection to the pan, you can notch the bottom to fit over the tiling flange - use KerdiFix on that seam when you band it to the pan."


"Personally, I like the idea of no caulk, and would seriously look into profiles and expansion joints"

Sorry this may be a dumb question but where you recomend notching the kerdi board to fit over the flange of my shower base, I am not sure what this means. I am useing a shower base not a pan and figured I would just have the kerdi board just up from the top of the shower base lip maybe 1/8" or so above it and then use the Sikaflex to seal this gap. Then the tile would hang down past this over the flange stopping just a little before the shower base decking and then finally fill that space between the shower base decking and the tile with silicone. As shown in the photo attached here. So I have two questions....

1.Iam I missing something Jim as I dont get what you are suggesting with the notch?

2. What is profiles and expansion joints where you say forget the caulk?

3.Also does anyone know if the Sikaflex shown in the attachment will work instead of the Sikalex Limestone Construction stuff as my building store only had the stuff shown here?...I can always return it if its not suitable.

Tiger Mountain Tile Inc
05-15-2015, 08:02 PM
#2: If you go to Schluter's site they have "profiles" in their menu on the left. You can see what he's referring to. Personally, I prefer silicone but that's what makes the world go 'round. :)

05-16-2015, 05:55 AM
Wayne, this is the type of Sikaflex Paul recommends, I've used it and the stuff is very sticky. You can buy it at Homers, I've included link below the picture. You can also order from Amazon, search on "Sika Corp. 90629 Sikaflex Construction Sealant"


05-16-2015, 07:58 AM
Click here (http://www.schluter.com/media/datasheets/wall-countertop_eng.pdf?v=201505160601) to automagically download a PDF from Schluter's site regarding their profiles.

wayne bergman
05-18-2015, 09:18 PM
Getting ready for the dry waller this week coming up. He should be here mid week so I have layed out the placement for dry wall to but up against the kerdi board for a little overlap with my shluder profiles. It took a little head scrathing for sure to get all the tile edges etc figured out so they will line up with my niche's. One of the showers is not exactly like I would like it for line up but it will have to do as elecrical is in the way etc and I did not get organized early enough to sort out everything ahead of time. It takes quite a bit of planning I am seeing here for stud location etc.

One of the photos show my efforts to fair and plumb out some of my studs. I have one stud that needs about 5/16" build up in the middle and tappered to zero at the top and bottom so I have built up its sides so its plumb and lined up with the other studs and then kind of done a back fill with the PLP to the stips for backing I put in to fair it out.

The tile hanging in rough position shows the tile I will use on the niche and helped me figure out my spacing etc for niche placement.

Yikes! I have been looking at prices for the shower doors for these two showers and because I went with the oversized shower base at 66" the glass is a custom order and big bucks. I am leaning towards a barn door style sliding panel with one fixed panel instead of the hinged doors I was originally looking at but still it is super pricey. It may cost 1300 dollars Canadian for each each set of shower doors and that is if I install it myself. Whats with that? It seems kind of expensive for what you get in my opinion.

wayne bergman
06-03-2015, 09:04 PM
Drywall is just about complete now on this project so I have been able to make some headway with the kerdi board and I am just about ready to start the tile.

The treatment at the bottom of the kerdi board where it meets the shower base went well I think. I was hesitant on it as the schluder site shows the kerdi fix and the thin set treatment to the kerdi band all done in one slick operation and I knew I would not be able to duplicate what I saw on the video so easily but it went OK. I used siki flex instead of the kerdi fix and it sucked the kerdi band nicely into and against the shower base. I just was not sure about the calking being wet and also the thin set being wet and trying to squeeze everything in place with out making a big mess. Turn out it was not as bad as I thought so I will most likely use the same method for the second shower as well. I plan to complete one shower to finish and then start the second shower in the second suite afte the first one is done.

I have a question regarding my first row of tiles. I normally do the very bottom row first and prop it up off the tub deck with spacers to get everything level when I have done tub shower combo's before. This is my first tiled shower that has a fiber glass style shower base and I see other people tacking on a cleat for the second row and starting with the second row and then filling in the first row the bottome row at the end. I just want to make sure I am not missing something and there is a good reason to doing it this way. I would prefer to do the bottom row first and just wedge them so they are 1/4" or so off the shower deck and then work up from there. Is this OK ? It seems to have worked OK for me on a previous tub tile project but thought I better check.

Thanks in advance.....wayne

wayne bergman
06-03-2015, 10:58 PM
Yikes I see when double checking my bags of thin set they are actually Modified thin set. I specificly asked for non modified thin set at the suppliers and they knew I was laying porcelin tile to the kerdi board as they sold me all of it. I have read to use only un modified thin set and now i see I may have the wrong stuff.

Is anyone familiar with the polymer thin set show in my photos here? I have already used it for securing my kerdi band to the kerdi board etc. Should I buy un modified thin set for my tile setting or am I OK with what I got?

06-04-2015, 07:00 AM
Hi Wayne,

You don't need a ledger board to begin setting tile since you have an acrylic pan. Just do your layout, prepare the bottom tiles and start at the ledge of the pan.

"It may cost 1300 dollars Canadian for each each set of shower doors and that is if I install it myself."
That should be the approximate price including installation from a glass shop. Depends where you reside, I suppose. Custom tempered glass and the hardware for it is just expensive.

It's not a problem that you used modified mortar to install the Kerdi membrane over the board. Just will take longer to cure. It does go against Schluter's instructions though. Better get a premium unmodified thin-set mortar to set the tiles.

The shower is looking great so far!

wayne bergman
06-04-2015, 08:01 AM
Thnaks Ron, good advice. I will source out the right thin set for my tiles today. If the modified stuff I used for appling the Kerdi Band takes a little longer to set how long should I wait before setting the tile. Just a day or so?

Thanks Wayne

06-04-2015, 08:07 AM
Yes, by the time you get to setting tile that will be fine. It's very thin and will continue to dry even under the tiles.

wayne bergman
06-04-2015, 09:54 AM
THanks Ron. .....One more quick question. I wonder how much thin set I will need for the two showers. I am going all the way up to the ceiling and the base is 36" x 66" so its a little oversized but not huge. I am guessing 4 50lb bags in total for both showers?

wayne bergman
06-05-2015, 05:54 PM
Well I got my unmodified thin set and finally started on the first shower. I think my mix was a little dry so I will try wetter tomorrow but things are going good I figure.

06-05-2015, 06:17 PM
Hi Wayne,

Yes, 4 bags is a good guess.

06-05-2015, 06:18 PM
It's looking good!

wayne bergman
06-05-2015, 09:20 PM
I am liking the unmodified thin set I have found today. It is white but this is all they had. It is 118.1 so its unmodified and I am assuming its OK that it is not grey and just as good as grey?

Just curious is it just the sand that is white in this mortar so the mortar ends up looking this white?

The mortar on the first few tiles were too dry a mix for sure now that I see how nice it trowels on being a little wetter. The first mix was sticky so I am assuming it will be OK for strength but I have a better feeling about things now with the wetter mix.

Its funny you forget when you only do this once every couple of years and it takes a few hours of trial and error before things come back to me it seems.

06-05-2015, 09:53 PM
Looks like it's coming back to ya, Wayne. Just like riding a bicycle.:tup1:

06-05-2015, 10:06 PM
Some say that the white mortar ends up being slightly better than the grey...it needs more quality control to keep it white. Other than that, there is no functional difference between them.

06-05-2015, 10:06 PM
It's probably too late now but if you would have centered that wall with a grout joint in the middle, I think you would have had large cuts in the corners. Not the end of the world though. :)

wayne bergman
06-06-2015, 09:21 PM
Hey thanks Guys. Yes Davy you are right about the layout. I have a second shower to do so that one may have a different layout.

A couple of questions still please......

1. The thinset I got must have been stored in some kind of dampness as the bags are a little stiff. Before I add the water and mix you can see some hard balls of thin set that need to broken up and everything seems fine after it is all mixed up but wondering what I can say to my supplier? Is this kind of normal and nothing to worry about. My wife picked it up for me so she did not know the hard stiff bags are not ideal. Should I phone the place I bought the stuff from and complain or is this no big deal?

2. In one of my corners I will have a good 1/2" of space where the one wall of tile meets the other wall of tile. Is it worth filling that void in with thin set before I tile the next wall so the grout does not fill in that void when grouting or is the grout just as good as the thin set to fill in that void.

3. THis is probably a dumb question here but just want to make sure ....The top 1/4" at the ceiling between the tile and the sheet rock ....I go with silicone here right and not grout?

Thanks in advance......wayne

06-07-2015, 05:13 AM
Hi Wayne,

I wouldn't return those bags. If the balls get broken up during mixing, it's okay. Not ideal but not a problem to make a fuss over.

Just leave a gap for now.

At the top, I prefer to grout against the sheetrock ceiling; looks better.

wayne bergman
06-07-2015, 08:16 AM
Thanks Ron.

06-07-2015, 06:20 PM
re the shower glass. i had 2 panes of glass (curb to ceiling) along with a door installed in my basement shower. cost me $1600 Cdn including HST, guess because it was custom. all glass companies seemed to be +/- $100 in my area. by far the biggest expense i incurred. but just think of all the $ you are saving by doing the other stuff yourself....

wayne bergman
06-07-2015, 09:10 PM
I have found a pretty good deal at home depot for the barn door style sliding frameless. Not really frameless but pretty close. Even with the 66" oversize I got them for 1,000.00 CND including tax for each shower so it payed to shop around. I could have spent 3,000.00 for hinged framless for the pare of them if I just plunked my money down at the first place I went.

wayne bergman
06-08-2015, 06:36 PM
I am now finally at the point of dealing with the niche. Looks like I got lucky on the line up so things should go good tomorrow. I also thought I would show a picture of the tile saw I bought from Harbor Freight. It seems to be good value for the money. I got it on sale as well and it is sure nice having the ability to support the tile along the full 24 inch length when cuttting down the length of the tile. I have also owned a nice MK 14" brick saw over the years for making pizza ovens but it was no good for cutting long lengths of tile.

wayne bergman
06-10-2015, 10:08 PM
Grout tomorrow so looking forward to that. I am using a product called TEC Power Grout. I have started the kerdi board on the second shower and it is going smooth now that I have done the first one I am confident for this second shower.

06-11-2015, 12:21 AM
Looking good, Wayne. :)

Be sure to wash down the walls with a damp sponge before you start grouting. That'll remove any surface dust and make cleanup much easier for you.

wayne bergman
06-14-2015, 10:06 PM
I am wondering about the two products shown in the attachment. I want to go with a sanded silicone caulking I think at the vertical corners and also up at the ceiling where the tile stops at the ceiling and the tile meets in the corners. I think the polyblend stuff is left over from a bath tub I did years ago so hence the old lable. I remeber it seemed to work good although we onlys stayed in the house for a few years so I dont know how it stood up long term. The product called " Commercial 100% Silicone Caulk my wife picked up for me at the local floor store. They charged me 30 bucks for this tube after the tax was added. This sounds just rediculious and I plan to return it as when I tried to apply some of it to a test piece I could not get the stuff to come out of the tube. Must be old stock or something.

I am in Canada so its not always easy to get some of the products available in the states but any tips on what may be best to shop for in a sanded caulk. I want a sanded caulk for the look of grout but the ability to not crack in an expansion joint.

thanks in advance Wayne

Tiger Mountain Tile Inc
06-14-2015, 10:22 PM
Hi Wayne, My personal opinion is to do the exact opposite. The tube on the left is 100% silicone and is a much superior product to the acrylic product on the right. The silicone is harder to install and more work but if done correctly will last the life of your shower.

FYI, you have to poke a long wire or something down the tube to break the seal. Sometimes your caulk gun will have a metal wire attached.

wayne bergman
06-14-2015, 10:40 PM
Thanks Tiger, yes I sure did poke a hole in the seal. After a 5 inch woodworking awl did not do the trick I shove an 8" kniting needle down the through the tip into the tube. I was shocked when I pulled it out and no caulking was stuck to the kniting needle at all. Its was like the silicone was soft enough for the needle to go into the product but it was not fresh enough to stick to anything. A squeezed with all my might on the calking gun and nothing.

Tiger what about the price,I dont like the idea of spending 30 bucks on a tube of caulking

Tiger Mountain Tile Inc
06-14-2015, 11:01 PM
Is $30 worth it for the problem it solves? No need to recaulk? The acrylic will mold and need to be redone. The bright side is that it's easy to redo. That caulking (silicone) is probably in the neighborhood of $15-20 contractor cost down here + tax.

When I use CBP grout I use that caulking. When I switched over to that stuff my callbacks dropped to near 0. For me, it's well worth it. But it is more expensive, harder to install, and takes more time.

Not trying to hard sell you but just relating my experience. :)

ps. To back track a little bit because I feel like I'm making promises- sometimes there will be gaps in the caulking that develop in the first week or so. Those are just areas that didn't get caulked properly the first time.

Also, mold will grow on the caulking but the caulk itself doesn't mold. Just trying to set the expectations. :)