# 12" tile and Kerdi



## wannaBelkhuntin (Jan 3, 2009)

Is there a problem with installing 12" tile over Kerdi. Another guy was looking at a job I gave a quote to and told the people that you can't install 12" tile over Kerdi, that makes no sense to me. What's the difference whether it is a 12" tile or 4 6" tiles.
Thanks guys, Dave


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## Tylerwalker32 (Jun 27, 2011)

Yes you can, you just have to follow the manufactures instructions. As long as you do that your good.


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## angus242 (Oct 20, 2007)

You can install pretty much anything over Kerdi.

There's an at least 2" rule over Ditra.


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## JohnFRWhipple (Oct 20, 2009)

Many 12" tiles come with recommendations for "Modified Thin-set" Kerdi wants "Non-Modified Thin-set".

So the endless debate.

Your building inspector will require you to follow all the manufactures guidelines. So find a tile that recommends "Non-modified thin-set or switch out the Kerdi to something a little more installation friendly.

That would be pretty much every other product in North America and Europe. :whistling

This "Non-Modified stand of Schluter's is insane and the chain effects have resulted in all our code books getting a "Double Text" of sorts. Lines like use modified thin sets unless the manufucture requires non-modfied.

Now the Kerdi boys out there will come in and say "Stop picking on Schluter" "I use modified all the time". Do yourself a favour and follow the rules set out by your local building inspector.

His rules are "All products to be installed as per manufactures written guidelines." Those state non-modified.

This round and round is the exact reason I enjoy working with products like Noble Seal TS, Aqua Defense, Hydro Ban, Red Guard, 315 and on and on....


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## JazMan (Feb 16, 2007)

There is no reason not to use 12x12's over Kerdi. You and use any size, it makes no difference. 

Did the other guy give a reason?

Jaz


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## Floormasta78 (Apr 6, 2011)

The reason is because he is a moron and has no clue what he is talking about


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## country_huck (Dec 2, 2009)

Floormasta78 said:


> The reason is because he is a moron and has no clue what he is talking about


Agreed!!!!


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## Anderson (Sep 7, 2009)

Angus you said pretty much anything. Is that lawyer language or can you tell us what is not allowed. Just want to know so I don't scew up and put something down I am not suppose too.


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## angus242 (Oct 20, 2007)

Some glass tile manufacturers will want their stuff installed with very specific materials. If Schluter won't allow those setting materials over their Kerdi, you technically cannot use that tile.


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## Anderson (Sep 7, 2009)

Not 100% about this but I was told that if its a glazed tile you should use a epoxy thinset as the cement will corrode the backing in a matter of years. Is this what you are talking about.


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## Splinter (Apr 5, 2005)

Yeah, anything but glass over Kerdi...

Oh...wait....


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## Terrorron (Nov 7, 2008)

wannaBelkhuntin said:


> Is there a problem with installing 12" tile over Kerdi. Another guy was looking at a job I gave a quote to and told the people that you can't install 12" tile over Kerdi, that makes no sense to me. What's the difference whether it is a 12" tile or 4 6" tiles.
> Thanks guys, Dave


The guy's full of .

How many Kerdi showers have you done?

Ever try to remove a (cured) large format porcelain tile, set on Kerdi with a high quaility non-modified??

I have. 300 x 600 x 9.5 millimeter 

They don't come off...at all. 

Wellll...actually, they do. :whistling

In little itty bitty pieces.:blink: 

End of discussion.


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## Ceramictec (Feb 14, 2008)

Floormasta78 said:


> The reason is because he is a moron and has no clue what he is talking about


no, its because he thinks you can only use modified to stick tile, when in reality you can use a non modified and also get a good bond. 




JohnFRWhipple said:


> Your building inspector will require you to follow all the manufactures guidelines. So find a tile that recommends "Non-modified thin-set or switch out the Kerdi to something a little more installation friendly.


where do you come up with this crap from ?


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## angus242 (Oct 20, 2007)

Splinter said:


> Yeah, anything but glass over Kerdi...
> 
> Oh...wait....


I did say "some" and "technically"....


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## JohnFRWhipple (Oct 20, 2009)

Ceramictec said:


> ...where do you come up with this crap from ?



Brian if you call any building inspector they will quote to you "Product must be installed as per manufacture's guidelines."

Fact.

Easy to confirm. Just call your local building inspector.

I think the big difference is that I do permitted work every week and follow all the rules and many installers do renovations and have no inspectors to worry about.

On every roll of Kerdi it says to use non-modified thin-set. In the TCNA Specification guide (Tile Council of North America) it states in every single shower detail that if glass tile is to be used that it is the manufacture of the tile that needs to specify the setting material. 

No where Brian does it say you can use modified.

Unless of course you go through all the trouble to get a Schluter rep to come and sign off on the tile, the setting material and even then it would only be for that one job.

Your statement Brian leads people to believe it's OK to use modified thin sets when in fact you are not following the written guidelines that the building inspectors require you to follow.

Call Schluter Brian.

Call your local building inspector.

Maybe ask your clients if they don't mind you using your own system.

But really why. Kerdi is 8 mil thick. The thinnest protection in the industry I think (Is there a thinner product out there?). Over seas it's used mostly on walls and the 20 mil product used in steam rooms and wet zones.

Noble Seal TS is 30 mil.
Hydro Ban 20 + mil

All of these products 2.5 - roughly 4 times the thickness of Kerdi.

A homeowner or young installer starting up in this business would be well servered to do this research.

A credit card is 30 mil thick. Thick about it. Kerdi is roughly 1/4 the thickness of that. Scary!


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## slowsol (Aug 27, 2005)

JohnFRWhipple said:


> Many 12" tiles come with recommendations for "Modified Thin-set" Kerdi wants "Non-Modified Thin-set".
> 
> So the endless debate.
> 
> *Your building inspector will require you to follow all the manufactures guidelines. So find a tile that recommends "Non-modified thin-set or switch out the Kerdi to something a little more installation friendly.*


You guys must have some very strict inspections up there. I don't think you would even find a building inspector here that know the difference between modified and non-modified. :blink:


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## andeeznuts (Feb 21, 2008)

ive never heard of a building inspecter giving a crap about tile


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## katoman (Apr 26, 2009)

andeeznuts said:


> ive never heard of a building inspecter giving a crap about tile


O ya, sometimes they do. A local builder here got caught laying mesh and just filling the mesh. That does not meet TCNA spec. The inspector had them rip all the tiles up in about a dozen homes.

Get a TCNA manual.


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## JohnFRWhipple (Oct 20, 2009)

katoman said:


> ...Get a TCNA manual.


THANK YOU

And in the TCNA manual it will say in numerous cross sections and building details to use "Modified Thin set unless the manufacture requires you to use Non-Modified. In fact anywhere there is reference to a Schluter product it will have both options.

Same as the TTMAC.

So in order to follow TCNA guidelines, TTMAC guidelines, Schluter System guidelines and your local building departments guidelines when working with Kerdi you need "Non-Modified" thin set. Says so right on the instructions. Schluter customer service will confirm this and no one from Schluter will write you back saying it's OK to use modified. No one.

So if your tile manufacture recommends "Modified Thin Set" to set that new Carrera Marble or Large glass tile you are $%%^& if you have Kerdi on the walls.

Who thinks the TTMAC and NTCA wrote all these double options for no reason. These manufactures guidelines are to be followed and are what building inspectors look for.

I get the feeling that Vancouver is a tough city for these inspections but I don't know any other way. For years my inspectors when asked questions from me continue to state "Yes, as long as it's CSA approved and you follow all the written installation instructions."

I read that Kerdi is OK to install over drywall and asked my inspector here in North Vancouver if I can do this. He said no. I told him Schluter says it's OK and he still said no.

It is the building inspectors that ultimately call the shots, not some dude on an online forum. Even if you have no inspections on your project you should understand what is required. Even with no inspections we still flood test our projects - why, because it's required by code.

I bang out this long winded answers mainly because so many jump in and give out false information. If you are researching your home's shower construction do yourself a favour and go down to city hall and just ask a few questions. You'll be glad you did.

If you use modified thin set to install over Kerdi you do so at your own risk and have deviated from the manufactures written instructions. To then spread this information as acceptable procedures is wrong since your passing along miss information.

If your local Schluter rep told you it is OK ask for it in writting. If he does not send an email or letter send one to him like this.

"Further to our conversation last year _____ I finished the shower project on ______. I used modified thin set like you told me I could and the job came out just fine. Thanks for your help and letting me use modified thin sets on this project. Can I use modified thinsets on my next project to install my tile over the Kerdi?"

What type of reply do you think you will get? All you Kerdi Boys should "Re-Set" and ask for this permission letter. Once you get it share it online.

JW


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