Cement over cork underlayment

I had a question about cork underlayment. Usually it is applied over cement, but is there any code or reason against having cork underlayment sit between a concrete basement slab underneath and a deck mud cement on top?

The next layer is a thin layer of Redgard waterproofing membrane on top of that, then a heated floor mesh w/ wire, then mortar, then ceramic tile.

How would the inspection be rated for this?

Were you able to see how the cork was bonded to the concrete? If it had solid bonding, it shouldn’t be a problem.
I personally never used cork underlayment for tile, but I know they do make it for that.

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Go here and scroll down to “How do you install cork underlayment under tile” and watch the video.


There is a code requirement for R10 rigid insulation for heated floor (under concrete). I’m not sure if cork would meet that requirement or be suitable for this application.
Clarification - if codes requirements are important for you go to the code book that was adopted in your area. Codes can be very different depending on your location, especially energy codes.

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All good. Google CeraZorb®.

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