Repairing and levelling an internal party wall

[Omni5la5h]

I am going through a lot of renovation work at my house, and not sure why I've waited all this time to ask for some advice in these forums! Anyway, currently we have stripped two bedrooms upstairs quite heavily. They have no ceilings now (that was a fun job) and the brick walls have also been stripped back to the brick. Both rooms sit against the party wall.

We recently had chimneys removed and so the chimney breasts on the first floor have been stitched backed up and filled in, which is part of this party wall.

I am planning to install some soundproofing to this party wall. Currently looking at the foam backed plasterboard options as do not want to lose too much space. I think these are about 30mm. Any opinions on this most welcome too.

This wall is not quite level and also has a few holes where previous areas have been chased out. I am looking for some advice on what to use on the walls to fill in these gaps, and if also I should use the same thing to level out the wall where required. Some of the holes are in brick, but some are in the cinder blocks (see attached images). I think I read somewhere that I should use some epoxy repair stuff, but wondering what is most suitable here?

Thanks in advance

 

[foxhole]

No point filling if you are boarding over the lot.

 

[Omni5la5h]

Thanks for the response.

From what I've read the wall should be relatively flat and then the board is fixed using hammer fixings to the party wall. The recommendation was to have as little gaps and pockets as possible to further aid soundproofing. There are parts where I'll need to add something over the bricks to just bring it slightly more level. What should be used for that?

 

[foxhole]

Thanks for the response.

From what I've read the wall should be relatively flat and then the board is fixed using hammer fixings to the party wall. The recommendation was to have as little gaps and pockets as possible to further aid soundproofing. There are parts where I'll need to add something over the bricks to just bring it slightly more level. What should be used for that?

I would just glue on with foam adhesive.