i have to soundproof a small pokey cupboard room for an old lady who has a bunch of students moving in next door, i was going to fix battens, rockwool then sound block board then skim, would a parge coat before i fix the battens make any appreciable difference and would double boarding be a better bet than single sound block, any ideas would be much appreciated as i want it as quiet as possible for the old dear. or i could just nick the batteries to her hearing aid.