Underlayment for vinyl plank flooring on cement slab radiant heat

1951k

what type of underlayment do I need for installing vinyl flooring on radiant in slab heat?

I read that synthetic cork was good choice and should also add vapor barrier 4 ml type

We use gas to heat the floor system if that makes a difference.
Thanks for your help

Jamie Hall

I'd think cork would be a decent choice. Gives a little flex, which you want, but isn't that good an insulator. Vapour barrier? The question there is is this a slab on grade, or is there an air space beneath it? If it's slab on grade, the vapour barrier — and heavy insulation! — needs to be below the slab. Otherwise I'm not sure why you'd need it. But… I suppose if the space below was earth floor, for instance, I'd want it but again, underneath.

hot_rod

I'd check with the manufacturer of the brand you are considering for installation details.

When this thin cork is used as an underlayment it has a vapor barrier built into it.

Perhaps a liquid sealer then the tiles or planks?

I used cork tiles in a Tiny Home build and it had a thin wood backer to it.