GazTech

[quote=t5_nel;17456]Thanks dave, the issue is now that the levels will be wrong because some rooms will not be lifted ( as they were not bitumen/wood substrate to start with).

I will check the adhesive guidance but I am very interested to know if you can get away with thinner ply on top of concrete slab floors...[/quote]Tim a 6mm cement backer board can be adhered to the slab floors.Also a 6mm cement backer board ring nailed will be less labour intensive on the parquet flooring, but be sure to use a flexible adhesive and grout on these areas.