I am planning to convert to a waterborne underfloor heating system and am considering whether I need to lay insulation boards above what we believe is an ERGE floor structure before I use self-leveling compound. There is a small crawl space under the floor structure, and we estimate it's about 40 cm deep (we haven't made a hole in the floor yet or have drawings to confirm this).
Some builders say that if you use self-leveling compound to embed the pipes, insulation boards are not necessary, while others say that insulation should still be added. Does anyone have experience with this and can advise whether the insulation is really necessary, or if it's fine without?
