Hi, house from 1968 renovation of a bathroom with a cast floor. Previously, it was cast against the sill and raw boards against the outer wall and cast against the raw boards on the other walls. What is best to do now? Place a diffusion-tight plastic against the sill and a bit up on the plywood or glue polystyrene on the walls?
Additionally, there was 50mm polystyrene between the concrete and the house slab. Is that sufficient for underfloor heating in the bathroom in southern Sweden?
Best regards