In article ,
Ian_m wrote:
Should I just replace with plain 15mm or would moisture proof and/or
sound deadening (as my sons bedroom is directly above) be more suitable
? Any thoughts ?

A double layer of plasterboard (thick type) is the cheapest way of
increasing sound insulation.

--
*Dance like nobody's watching.

Dave Plowman London SW
To e-mail, change noise into sound.