A couple of weeks ago I took the plasterboard off a party wall in one of our bedrooms, only to find no sound proofing material in the cavity at all.

The wall was constructed as follows: One layer of 16mm plasterboard (my bedroom wall), then the cavity, then another layer of 16mm plasterboard (their kitchen wall).

I put Earthwool soundshield batts in the cavity and sealed it all back up.

I haven’t heard anything from next door since.

I’m going to glue a layer of 6mm cork over that.

I guess I’m “lucky” that I’m an owner occupier and can do work like that.

But I have no idea on how to deal with the washing machine, it’s coming from somewhere else but I couldn’t identify the apartment (could be from anywhere).