Subfloor required below wet ufh.

[Gaz81]

What subfloor should I be putting in below wet ufh. It's an old property (tile over soil at the moment. Am I close in thinking to excavate 225 below FF then lay 75mm compacted type 1, sand blinding, 1200g DPM, 100mm PIR, 500g DPM and 50mm flowing screed over clipped pipework with a perimeter expansion strip. 

 

Cheers, Gaz. 

[Temp]

That sounds fine to me although I think 50mm screed might be a bit thin. Think 65mm is more standard. However i have heard some BCO insist on hardcore, concrete, insulation, screed. 

 

Compact the ground before laying hardcore. Perhaps Compact the hardcore in two layers?