Basement party wall. Does it need tanking?

[graham.89]

Hello there!

I am currently looking to repoint and render a wall between us and the neighbours whilst the adjoining wall is due to be tanked. The wall between us and the neighbours has been taken back to the stone masonry and I wondered what to point it with and whether to attempt tanking it also…Further to that, can I work on it up to a certain level or does the whole wall need to be done..? It’s below ground level (we are built into a hill) and I’m a rookie so any advice would be greatly appreciated! Please see picture attached…TIA
Oh and the house is pretty old (late 18th century).

 

[blup]

You don't say if there is any existing damp. I would plasterboard that frame to allow the wall to breathe, especially as the other side is being tanked, and keep it under review. If it's built into a hill it's tantamount to be being a cellar. These youtube videos are helpful in understanding some of the issues:

Blup