sound proofing under floor for party wall

[burgensteen]

Hi,
I have a 3 bed semi & on my ground floor it is joists with a gap under of a foot or so.
I am after insulating between the party walls downstairs and wondering what to use and how to fit it.
I dont want to cause damp and have no idea how to fix (whatever you guys recommend) or exactly where to put it (right up against wall, leave a gap, etc).
Do I put it all the way to the dirt floor or just as far as the bottom of the joist & if so how do I fix it.

Any help much appreciated.

Thanks Jon

 

[rules&rulers]

Have a look at this site http://www.soundservice.co.uk/

 

[^woody^]

What sound are the neighbours making under their floor, that is passing through the wall under your floor?

Normally you would just seal any joist gaps with acoustic expanding foam, and insulate the floor.