Hi,
I'm laying PIR insulation boards on my slab in preparation to clip underfloor heating pipes to it. The problem I have is that I have had to cut the boards around my water feed pipes running across the room, so I have channels which I need to fill to prevent the screed cracking when it's laid on the UFH pipes. What should I use to fill these channels? Would sand work? I've blinded the PIR boards on the slab using sand.
I'm laying PIR insulation boards on my slab in preparation to clip underfloor heating pipes to it. The problem I have is that I have had to cut the boards around my water feed pipes running across the room, so I have channels which I need to fill to prevent the screed cracking when it's laid on the UFH pipes. What should I use to fill these channels? Would sand work? I've blinded the PIR boards on the slab using sand.