I was thinking about our slab insulation and UFH today. I noticed that our architect specified screed for the UFH. The slab make up is below.   GROUND FLOOR: Ground floor to be constructed of 70mm self-levelling concrete screed incorporating underfloor heating system, on 150mm KOOLTHERM K3 Kingspan insulation, on 125mm thick structural C35 grade concrete slab, to be laid with A252 mesh reinforcement as per engineers details at 50mm bottom cover, poured in equal sections and placed onto