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Vinyl flooring with cork underneath

I am installing a new bathroom floor. I plan on getting an electric underfloor heating mat, 2 backer boards for under the heating, screed the mat and tile over this.

My question is can I place the back boards on the cork vinyl(even though it's got glue on top) or do I need to remove the cork.

Another option is cleaning the glue off the cork and using the cork as the subfloor. Is this possible?

Thanks for the help, first timer here.

isherwood
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Jamie Smith
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  • Cork is bork. The top three [backer manufacturers require](https://diy.stackexchange.com/a/51787/23295) *minimum* 5/8" exterior-grade OSB or plywood. – Mazura Dec 28 '19 at 23:43

5 Answers5

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When I am redoing a bathroom and adding the needed backer board to a subfloor assembly, I would remove all existing finish floors no matter how many to get back down to the original subfloor. Then evaluate that, repair it if needed, add to it if needed to make it stiff enough for tile, then add the one layer of 1/4" backer board, then the heating wires, screed, then thinset and tile.

All these layers together will add up to a reasonably thick floor, if the all original flooring is not removed, you will have a potentially sizable rise in height from one floor to another

Jack
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    I concur. You'll want to get down to the most stable, sturdy base. I'd strip any/all old flooring layers off (to the joists, if necessary and replace the sub-floor with 3/4" plywood.) Any/All movement or "springiness" will crumble your grout and maybe crack your tiles eventually. – gnicko Dec 28 '19 at 16:41
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I've never had to do this (install tile over cork), but I think you need to remove the cork.

Backer/cement boards needs to be firmly fastened to the sub-floor. Any kind of softness, give, or "springiness" will be transferred up the tiles and will cause the tiles or the tile joints to crack.

SteveSh
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  • Idiots who did our bathroom before we owned this house, appear to have done this. Cracked tiles and ones that move (*not noticable when you walk on them) is the end result. – djsmiley2kStaysInside Dec 28 '19 at 22:44
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If you read James Hardie installation you need to thinset the board down with modified thinset so over cork no don't do it

user110568
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  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably [take our tour](//diy.stackexchange.com/tour) so you'll know how best to contribute here. – Daniel Griscom Dec 29 '19 at 02:25
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You can check with the heating mat manufacture to determine if the cork is a suitable subfloor. But I don't think that cork is a good underlay for tile. It's too soft.

The target finished height of the floor is a key consideration. If you install materials over the top of the existing floor, the new floor level will be higher. That can be awkward, especially in a bathroom. To stay at the current floor height, you need to remove something before adding something.

Jasen
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Charles
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Do not ever tile over cork.

Unless you poor a 5ft thick layer of concrete over it 1st. Then it might work.

Ted
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