Polyflor with wet UGH

Hello,

I wonder if you can help or adivise, we are having an externsion to our 1930's house, the existing kitchen is a solid floor, the dining room is raised timer.
The wall between the two is being removed to open this up.

The extension to the rear will also be riased timber to match the existing dining room & i will also be digging up the existing kitchen floor to become riased timber. (the rear wall is also coming down to open the old to the new)

My plumber is fitting wet UFH & insulating the floor with celotex.

My question is that we are lookking to use Polyflor LVT, either camaro or affinity - what is the recommended subfloor build?
celotex --> screed (sand cement mix) --> marine ply --> polyflor

Any help will be great.

Many thanks

sean

 

Miss out marine ply and have a screeding compound instead

 

Thanks for the reply, I thought you had to have marine to stop any floor movement?

 

Flooring grade ply yes but not marine ply, it will be either fg1 or sp101

 

Hi
Thanks for the reply, could i use fermacell 2 E 22 Flooring Overlay instead on the flooring grade ply? so the floor make up will be
100mm celotex -> 15mm UFH pipe with screed over flush up to joist - (total 25mm from top of celotex to joist) > then fermacel board then floor finish?