I was trying to find concrete/screed floorboards that can be used as the structural floorboard and at the same have the grooves for the underfloor heating pipes.
The idea of using a concrete/screed floorboard is to have better thermal conductivity and less height instead of using floorboards and then a underfloor heating panel on top.
There are regular chipboards for underfloor heating that I'm also researching about, but considering the pricing, it may be better to just use regular chipboard and then additional underfloor heating panels on top.
If anyone has some advice on best options for underfloor heating in a loft, that would be great. I'm planning to use the same procedure on the 1st floor of the house later once we work our way down.