# Help for Tile install. Cork underlayment?



## andy1908 (Mar 25, 2009)

Hey guys,
So here's my situation. I'm going to be installing 13" x 13" x 1/4" ceramic tile in my kitchen. Currently have a plywood subfloor. Was thinking of using 1/8" cork underlayment. basically: mortar, cork, mortar, tile.

House was built in '88. 150 sq/ft is what im looking to cover. I really only have about 3/4" TOTAL height to install this stuff without creating a "tripping" point into the rest of my home. I've seen different options for underlayment: cork, schluter ditra, hardibacker, etc. Hardibacker is at a minimum 1/4", and schluter is pretty expensive. I'm just trying to figure the best steps and route to take with installing this. I've never done tile, but have done the remainder of my homes floors. Floating, sticky tile,







.

Just looking for some thoughts on IF the cork underlayment is a good idea, if so how should I apply it. If not, im looking for other suggestions.


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## ccarlisle (Jul 2, 2008)

Look, a big reason certain underlayments are suitable for tiling over is because of their greater resistance to crushing under weight. Look at Hardibacker...it is cement-based and virtually incompressible. Same for Ditra, although this is an engineered plastic. Same for plywood...OK I may be stretching things a bit here but this is just to show you why certain materials are used and others aren't. Cork isn't suggested anywhere under tiles...

And why are we looking for some "resistance to crushing"? so that when Fat Cousin Eddy who weighs over 280lbs comes over carrying a 25lb keg of beer and dumps it on the floor (a) the tiles or (b) the grout between the tiles don't crack. :whistling2:

But who are we to try and stop you? none of us will be doing the install nor would we if asked...it's your kitchen, your tiles and ultimately it is you who will have to live with cracked and crumbling grout...

You'll end up spending more to re do it than the amount you save hoping cork is your saviour.:yes:


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## andy1908 (Mar 25, 2009)

ccarlisle said:


> Look, a big reason certain underlayments are suitable for tiling over is because of their greater resistance to crushing under weight. Look at Hardibacker...it is cement-based and virtually incompressible. Same for Ditra, although this is an engineered plastic. Same for plywood...OK I may be stretching things a bit here but this is just to show you why certain materials are used and others aren't. Cork isn't suggested anywhere under tiles...
> 
> And why are we looking for some "resistance to crushing"? so that when Fat Cousin Eddy who weighs over 280lbs comes over carrying a 25lb keg of beer and dumps it on the floor (a) the tiles or (b) the grout between the tiles don't crack. :whistling2:
> 
> ...


damn, i like your style...
ok, so if i did end up going with the ditra system, would i be safe in doing the mortar, ditra, mortar system (basically what they say to do)? i'd rathe spend the extra $ if it's pretty much a give that the cork route will screw me in the end... thanks.
-a


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## HABSFAN2006 (Feb 25, 2009)

This is all and all a very bad idea. Doesn't seem like ceramic is the best option for you. 3/4" total thickness of plywood is not nearly enough for ceramic tile install. You need an additional subfloor plywood, or one of the products mentioned.

do it the right way the first time, and you won't be ripping it out withing 3-5 years.

If you only want ceramic "look", then look into floating or click type fake tiles. they come in 12x12 single tile parterns that are 1 tile wide, by 4 long. This is what I put in my kitchen, with a 3/8" plywood to give the perfect 3/4" rise you were talking about.


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## ccarlisle (Jul 2, 2008)

_..."damn, i like your style..."_
​Actually, I'm feeling pretty good with spring here and the snow almost all gone, plus the  hockey team in this city finally won a game...so I won $20...big deal. Normally, I'd be punchy...:laughing:

But Habsfan2006 is correct. Here's why: before any tile installation, you first have to see what subfloor system you have and if that subfloor system (which includes the joists and the span of those joists) is sufficient to put tile onto, without the tiles cracking - even without Cousin Eddy even in sight. Then you build the subfloor accordingly. Now tiling standards that we use specify that the subfloor must be 5/8" plywood or OSB, then the underlayment put on top of that. Let's take Ditra because it is the skinniest...here the order: bond coat of modified thinset/Ditra/ unmodified thinset/tiles.

In total you should get about 3/4" thick on top of the subfloor since Ditra is 1/8" thick. It's Schluter method DW16-T-08 and that assumes a thing or two about your joists and may or may not be applicable to your case, I don't know.

Now that's getting about as close to minimum thickness that I can think of. 

For 150 sq ft, the Ditra will cost you about $2.50 per sq ft...


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## HABSFAN2006 (Feb 25, 2009)

Good point on the thinset order, and very important...

and btw, you should be happy they won, and should be cheering 
nope your not one of those "boo birds" :laughing:


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## ccarlisle (Jul 2, 2008)

I am happy Montreal finally won a game...now if we could hold onto a playoff spot, my feet will gladly soft-shuffle right around the room...!

btw Ottawa is my home town; grew up in Rockcliffe Park, on Park Road actually. 

So why aren't you cheering for the Sens?


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## HABSFAN2006 (Feb 25, 2009)

ccarlisle said:


> I am happy Montreal finally won a game...now if we could hold onto a playoff spot, my feet will gladly soft-shuffle right around the room...!
> 
> btw Ottawa is my home town; grew up in Rockcliffe Park, on Park Road actually.
> 
> So why aren't you cheering for the Sens?


Live on the Ontario side of the border, not far in, but work in Mtl.
Been a Habs fan all my life, before the Sens got back into Ottawa...

You'd be supprised how many habs fans there are between kingston and the border...

go habs go! :thumbup:


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## gcernohous (Jun 4, 2009)

*Cork Under Tile - Yes*

I'm going to have to completely disagree with CCarlisle. Cork underlayment is STRONGLY recommended under tile and over concrete where in-floor heat is being used. It is used as an insulation to prevent heat loss. It is also highly recommended in construction such as condos and apartments to reduce noise from hard floor surfaces including tile.


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