# Cork Underlayment



## JDC78 (Mar 9, 2013)

Have any of you flooring guys used the 6mm cork underlayment under tile and over a basement concrete substrate? My HO wants to save on some money and use a green product. The slab is about 4-5 inches thick and shows no signs of cracking as of yet and the slab is about 15 months old. I have never used cork as a underlayment and wasn't sure if it would be good enough for a uncoupling underlayment? Also wasn't sure if a modified mortar would adhere to it. Please give me some input on the good and bad of using cork. 
Thanks for any input.


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## GO Remodeling (Apr 5, 2005)

You can search cork underlayment.

How will it save him money?

Rolled cork has memory and will try to roll back up.
I've used kerabond/keralastic to thinset cork to substrate. Then roll it and weight it to prevent rolling up.
Sheet cork might be better. Czerob underlayment,Ditra option might be better.


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## JDC78 (Mar 9, 2013)

Well the rolled cork is a lot cheaper than ditra and has the "green" stamp of approval. I didn't think about the rolled cork trying to roll back up on me as I put it down, so thanks for that. Just not sure if its a solid enough underlayment and or is able to withstand any movement from the slab and not transfer that movement to the tile. Also not sure about any moisture that may come from the slab and the impact that would have on the cork. I have used ditra and spider web several times and was happy with both.


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## GO Remodeling (Apr 5, 2005)

Cork is a fine underlayment but it isn't going to do what Ditra can do in your application. 
Do you know if the concrete was sealed?


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## ohiohomedoctor (Dec 26, 2010)

I like white wine with fish...


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## JDC78 (Mar 9, 2013)

No concrete was not sealed


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## Ceramictec (Feb 14, 2008)

cork isn't a bad thing, just not the upscale way to do it.
we did a lot in condos who require it as sound control.
we just did one last week using it and I haven't used it for years.

it has as much memory as Ditra does when rolled up.
just roll it up the other way fast and install.


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## astor (Dec 19, 2008)

I use urethane glue such as Bostik's best to adhere the cork, it prvents some moisture transfer from slab, I prefer 2'x3' sheets rather than rolls(cheaper too). In both case I roll with 100 lbs roller within 2 hrs.
The guys in Miami Dade require to put- I believe- 9mm cork on high rise buildings when they do wood or tile floors.


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## PrecisionFloors (Jan 24, 2006)

astor said:


> I use urethane glue such as Bostik's best to adhere the cork, it prvents some moisture transfer from slab, I prefer 2'x3' sheets rather than rolls(cheaper too). In both case I roll with 100 lbs roller within 2 hrs.
> The guys in Miami Dade require to put- I believe- 9mm cork on high rise buildings when they do wood or tile floors.


Same method I use as well. Moisture cured urethane will act as a moisture barrier once cured.


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## JDC78 (Mar 9, 2013)

Great input thanks guys


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## Ceramictec (Feb 14, 2008)

astor said:


> I use urethane glue such as Bostik's best to adhere the cork, it prvents some moisture transfer from slab.





PrecisionFloors said:


> Same method I use as well. Moisture cured urethane will act as a moisture barrier once cured.


that's pretty cool and would help on a first floor slab.

I use modified thinset. no need for anything fancy when
your on a raised floor in a condo or high rise.


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## JDC78 (Mar 9, 2013)

So you are talking like the Bostic TKO adhesive?
Or is there cheaper or better ones out there?


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## PrecisionFloors (Jan 24, 2006)

JDC78 said:


> So you are talking like the Bostic TKO adhesive?
> Or is there cheaper or better ones out there?


I like Mapei 975/980 it is cheaper than Bostik's and easier to get (around here). The 980 expands a little so bird baths are less of an issue, to the point I don't even fill them unless they are 1/4" or more. Once it cures it grips as well or better than any adhesive on the market as well. I've demoed them all...or close to it.


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## ee3 (Feb 10, 2006)

I would check the moisture being slab on grade.
Also per the TCNA cork require's Epoxy Grout (F-135)
Im assuming your NOT using Stone !(marble)


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## GO Remodeling (Apr 5, 2005)

ee3,
which Noble membrane would you recommend for this? (If needed at all)


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## ee3 (Feb 10, 2006)

If needed at all...CIS...it will do,moisture,crack,uncoupling...not sure you need it but.....


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## CO762 (Feb 22, 2010)

Never used CIS, but it sounds interesting.


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