77mm between concrete and existing tile floor
Hi,
we've been victim to an AWOL builder who has not left enough space for us to insulate with 50mm pir board, screed and then tile.
I was thinking 50mm PIR board over concerete, chipboard and then no more ply.
Should I self level the concrete, assuming the concrete is level but just bumpy or would the PIR board form a level enough base?
Could I just use no more ply on top or should I use a layer of notched chipboard? Thanks!