Mapei reno screed, over UFH, over suspended timber floor

[Annker]

I doing a full heating install into a victorian reno and at the minute the plan is to install UHF in two rooms.

Given the small areas that need covering, and limited onsite access, I am searching for screed options I can mix up myself onsite.

 

One room has a block & beam subfloor, therefore traditional sand and cement laid at ~65mm thick is the go to option.

The other room has a suspended timber subfloor so I am looking to save Dead load in this particular room, this can be achieved by using a liquid screed at 40mm thick.

 

The suspended timber subfloor is newly installed.

I have ran the numbers through ChatGPT and it can comfortably support the weight of a 40mm thick liquid screed laid on 100mm PIR.

 

Mapei ultraplan reno screed  looks like a potential option, it can be laid to 40mm an UFH compatible although I'm unsure if it is suitable floating on PIR on a suspended timber sub floor.

I don't have a specific concern, so just wondering if anyone has used it in a similar situation?

 

EDIT:

I called Mapei Tech and they advised that ultraplan reno is moreso a self leveling product and instead recommend using Topcem, however thhe minimum thickness it can be laid at is 55mm, so a weight increase that I will have to check 

 

Edited 15 hours ago by Annker