I'm in the process of trying to add soundproofing to a top floor flat which was badly converted from a terraced house. I've decided the single worst culprit is actually the partition wall between the stairs (in my flat, down to the front door) and the ground floor flat. I opened up a hole to explore and what I found is shown in this diagram:
It looks like when they made the partition between the two flats, they put up plasterboard directly against the side of the steps in the ground floor flat (actually touching the treads), left a gap, then cut two layers of plasterboard to fit the shape of the stairs and actually put my side of the wall directly on top of the steps themselves! Here is a frontal view to make things clearer:
Inside the 60mm gap, there are studs (which themselves touch/rest on the treads), and a bit of insulation).
The problem I'm having is not just my own impact noise into the ground floor flat, but also that I get a huge amount of airborne noise from their flat through this wall. Originally, I had been thinking of installing something like this -- DFM in the cavity and soundproofing wall board. But now I am worried this won't be sufficient, because if the treads directly touch their plasterboard and mine, won't this mean airborne noise is transmitted directly through the treads anyway?
If this is the case, is there anything I can do about it? I am thinking I may have to put down a layer of floor soundproofing over the exposed part of the treads and risers, but I wonder whether it might make sense to do this on the part inside the cavity, too?
Does anyone have any suggestions for this kind of situation? I'd like to work out something I can do with minimal disturbance to my neighbours.
Thanks for your help!!
Mark
